The first thing I was told on checking in at my hotel close to the beachfront in Tel Aviv was where the underground shelter was.

“Your room is on the sixth floor,” the handsome young manager said. “If you hear the sirens you have one and a half minutes to get to the basement. If you can’t make it, do this.” He gestured for me to follow him to the stairs. We went up several flights and then he stopped in a stairwell between floors. He pressed the palm of his right hand against the low, whitepainted concrete ceiling. “This is solid and offers some protection.” He shook his head and attempted to smile.

Tel Aviv is a city in shock, in a traumatised country that seems never to be fully at rest or peace – nor will it ever be while the occupation of the West Bank, which was seized from Jordan during the 1967 war, and the building of settlements there continue. The Gaza Strip, where as many as 1.7 million Palestinian Arabs live in desperate poverty, remains besieged and effectively isolated from the rest of the world.

On Wednesday 14 November, at the start of Operation Pillar of Defence, the Israel Defence Forces (IDF) struck inside Gaza, killing a senior Hamas military commander, Ahmed al-Jabari, the first in what would be a series of attacks on “strategic targets” that resulted in the death of more than 100 people, many of them civilians. The explanation for the surprise assassination that enraged the democratically elected Islamist government of Egypt as well as other Arab nations was that Israel could no longer tolerate missiles being fired by Hamas and other jihadist militants from Gaza at towns in the south of the country – there have been hundreds of such attacks this year. “We have no claim on Gaza,” the Israeli prime minister’s spokesman Mark Regev told me over dinner. “We only attacked to make the south safe.”

The border between Israel and the Gaza Strip is secured by a “smart fence” and is under continuous military surveillance and control. No Israeli is permitted to enter Gaza from Israel; very few Palestinians are allowed to enter Israel, and only in exceptional circumstances. There is a blockade of both the land and the sea routes into the benighted strip. Weapons and other goods and materials are smuggled into Gaza from Egypt through a network of underground tunnels.

“Two weeks ago a sophisticated tunnel that went from Gaza into Israel was discovered,” David Horovitz, a former editor of the Jerusalem Postwho now edits timesofisrael.com, told me when we met. “An anti-tank missile was fired at an Israeli Jeep 150 yards into Israel, injuring four soldiers. And the missiles keep on coming. The government can’t just leave Hamas free to try to kill us.”

Hamas, which is both a political party and an Islamist resistance movement and took its inspiration from the pan-Arab Muslim Brotherhood, was founded during the first intifada in 1987 and was democratically elected to power in Gaza in 2006. Its leadership responded to the death of al-Jabari and related attacks on its arsenal by declaring that Israel had “opened gates of hell” and firing off even more rockets.

On 15 November, for the first time since the 1991 Gulf war when Iraq sent Scud missiles into Israel, warning sirens sounded in Tel Aviv and its suburbs, the most populous residential areas of the country. Two rockets fired from inside Gaza travelled at least 70 kilometres towards Tel Aviv before exploding harmlessly.

Never before had a rocket fired from the strip reached that far. Tel Aviv, the tourist and commercial capital, with its sandy beaches and many bars and clubs, had become a reachable a target for Hamas’s Iranian-made missiles.

The next day, the warning sirens sounded again as a missile exploded close to the city centre but out at sea. And then a few hours later a rocket launched from Gaza landed in an “open area” not far from an Arab settlement on the edge of Jerusalem. Two more rockets were fired at Jerusalem on Tuesday 20 November even as peace talks took place in Cairo and Israel prepared for the arrival of Hillary Clinton.

Israel has called up 75,000 reservists and the IDF have made preparations for a land invasion of Gaza; out on the roads you saw many tanks being transported south. Israel is never more united than during war or conflict. The polls indicate considerable support for Prime Minister Binyamin Netanyahu (who just happens to be preparing for a general election in January) and for Pillar of Defence.

Under Operation Cast Lead, the name given to the three-week assault on Hamas in the winter of 2008-2009, Israel launched a land invasion of Gaza and as many as 1,400 Palestinians were killed in air and ground attacks, many of them civilians. The Palestinians have their own name for what happened – the “Gaza Massacre”. The question being asked while I was in Israel was this: would the Netanyahu government dare to launch another ground invasion this time around?

Many senior Israeli politicians and officials consider Cast Lead and the second Lebanon war, fought against Iran’s client Shia militia Hezbollah in 2006, to have been de facto proxy wars with Iran. But since the Arab spring, the long civil war in Syria during which the Iranians have supported the murderous Assad regime and the resurgence of Sunni Islam throughout the Middle East, Hamas has fallen much more under the influence of the Muslim Brotherhood in Egypt; its leader, Khaled Meshal, has left Damascus, where he had his longtime headquarters, and is now in Cairo, having first relocated to Qatar, a prominent supporter of Hamas.

Meanwhile, the long-established Sunni resistance movement Islamic Jihad has emerged as Iran’s chief client in the Gaza Strip and its operatives have also been firing rockets into Israel and supporting jihadists in the Sinai Peninsula. “We hold Hamas solely responsible for what Islamic Jihad does,” Mark Regev told me. “In our view, Hamas is responsible for everything that happens inside its territory and is accountable.”

Regev, who was born in Melbourne, Austra - lia, is a familiar media face: he was a government spokesman during Cast Lead and was retained as the prime minister’s spokesman by Netanyahu when he came to power. He describes himself as a former Marxist (and reader of the New Statesman) who came to Israel as a young man on a kibbutz, met the woman who became his wife and stayed. He is thin and dark-eyed and speaks with conviction and relentless fluency in a deep, resonant voice. He likes to argue. He became especially animated when I asked whether Israel was planning a unilateral strike on Iran.

“A nuclear-armed Iran is something we will not accept,” he said. “No serious person thinks that their nuclear programme is benign. We have little doubt that, by the middle of next year, the Iranians could have enough enriched uranium to make a bomb.”

He stopped eating and looked straight at me. “They call for wiping Israel off the face of the earth and we take that threat very seriously. We have thought about the possible blowback but the bottom line is that the challenges involved in trying to prevent Iran from proliferating are dwarfed by the challenges involved in dealing with a nuclear-armed Iran.

“You have to operate realpolitik. You need sanctions, economic, diplomatic and political pressure, but you also need a military option. The paradox is that if you have a credible military option you might not have to use it, and conversely if you take the military option off the table you are undermining the chances of a peaceful solution.”

It’s unequivocal that Israel would not hesitate to hit Iran if the Americans were not prepared to do it first, with all the dire consequences for the region and the world that would bring. The fearful reality of such action and what might happen after it – attacks on western and Jewish interests throughout the world, Hezbollah and Iranian rocket attacks on northern Israel, the closure of the Strait of Hormuz and a consequent spike in the world oil price, even a possible land invasion of Israel – has prompted a figure as powerful as Meir Dagan, who was director of intelligence of the Mossad between 2002 and 2011, to caution publicly against a precipitous strike against Iran’s nuclear programme.

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The Israeli government accuses Hamas of “double war crimes” – of targeting civilians in Israel while operating and hiding among and thus endangering civilians in Gaza, one of the most densely populated strips of land in the world. In spite of the terrible risk of bombing Gaza from the air and sea, the Israeli government believes its actions are morally justified because – it says – it acts only in response to aggression and provocation from militants and “targets” its enemies with “surgical” precision, using the most sophisticated missile technology rather than operating a policy of indiscriminate rocket fire.

But its intentions are not merely those of self-defence. “The goal of the operation is to send Gaza back to the Middle Ages. Only then will Israel be calm for 40 years,” said Eliyahu Yishai, minister of internal affairs in the Likudled coalition government. Yishai, head of the religious Shas party, is an unpleasant nationalist chauvinist and many others on the Israeli right and within the settler movement share his prejudices.

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On the morning of 17 November I went down to the beach close to the hotel in Tel Aviv. At the main marina I met Yuri Daniszewski, who works in security. “It’s very quiet,” he said, gesturing towards the shore. Although Yuri has a Russian name, he was quick to tell me he speaks no Russian. He was born in Israel but lived for 35 years in Antwerp, Belgium, before returning home “for a woman”.

“Usually on a Saturday like this – very warm – the beach would be full,” he said. “But you can see people are staying at home. It’s because of the rockets.”

As we spoke a fighter plane flew low overhead, disturbing the late-morning calm. Israel is an intensely militarised state and nearly every man you meet – and most women as well – has served in the army and been involved in combat operations of one kind or another.

Oleg, who greeted me at the airport, was typical. He, too, was from a Russian family that arrived in the country in the early 1990s. At the age of 27, he had served three years in the army and seen action near Hebron, in the occupied West Bank. He was feeling dejected: he was one of the reservists who had received his callup papers. “I was told yesterday I’ve to go back into the army. I’m going to Gaza.” I asked how he felt. “Like most people in Tel Aviv I’d rather go to the bars. I’m getting married in a few months – and my girlfriend is worried.”

At about 4.35pm that day, the sirens sounded in Tel Aviv: there was a strange, uneasy quiet and then you heard two thumping explosions. I left the bar in which I was watching the north London derby on a large wall-mounted screen and saw smoke in the sky where the rocket, or rockets, had been intercepted by the Iron Dome, the anti-missile defence system that has been in operation since 2011 and was introduced to the Tel Aviv area only that morning. For hours afterwards the skies above the city were restless with the movement of fighter jets on patrol.

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One morning I drove out to the city of Ramallah, the capital of the Palestinian Authority in the West Bank, to have coffee with a senior Fatah official named Husam Zomlot. He was convinced that Netanyahu had made a grave miscalculation of the “international mood”.

He lit a cigarette and leaned towards me in his chair. “He did not expect the response from Hamas he got – he did not expect them to fire at Tel Aviv and Jerusalem.” (Regev had told me that Israel had indeed known about Hamas’s new long-range missiles. “We knew they had 11,000 Iranian rockets and missiles, with capacity to reach Tel Aviv.”)

There had been demonstrations throughout the West Bank in recent days in support of Hamas. “This could be the continuation of the intifada,” Zomlot said. He rejects the terms first and second intifada. “The intifada has never stopped. What has happened in Gaza could bring all Palestinians together; it could create a new dynamic. We are seeing a reshuffling of the cards, a realignment of the stars. After the Arab spring, this is a new landscape. Last night in Gaza [Sunday 18 November], the 500 leaders who ignited the Egypt revolution in Tahrir Square were in Gaza showing their support. That’s a game-changer.”

Zomlot, who was educated at the London School of Economics and Harvard, was born and grew up in Gaza. “It used to be like a mini- Beirut. I have seen pictures of my mother in a miniskirt. It was very liberal, very liberated. Radical ideas flourished: communism, leftism. The national liberation movements were born there. Things began to change with the first intifada. Now, we have the siege, economic meltdown, hopelessness, helplessness. Hamas are in control of the education system. They were becoming very unpopular but now, because of what’s happened, their popularity is soaring.”

Zomlot, like many secular nationalists, mourns the fragmentation of the once-united Palestinian cause. He insists that Gaza must not be lost to the Islamists and, rather than being absorbed into the Egyptian sphere of in - fluence, must remain part of any future sovereign Palestinian state, with a clear, open land route across Israel linking Gaza and the West Bank, as would have to be agreed under any two-state solution.

The alternative for Israel is bleak: either the status quo continues and the fighting goes on or, unthinkable for most Jews, demographic pressures force the creation of a so-called bi - national state, in which Jews and Arabs have equal rights, which would mean the end of a democratic Jewish state. Either that, or Israel, in an attempt to remain Jewish, becomes a kind of a militarised garrison, or de facto apartheid, state.

One liberal Israeli academic and commentator, Alex Yakobson, told me that the “occupation [of the West Bank] was our greatest crime in 100 years” and that the Palestinians have never considered themselves to be the weaker side in the conflict. “They have time on their side, the wider Muslim world to draw support from, and this gives them inspiration and strategic depth,” he said.

Israel, by contrast, is surely too complacently dependent on its long-held alliance with the United States: it has great resilience as a nation but it lacks the flexibility to pivot among mul - tiple powerful partners in different spheres of political influence. “You can’t have two and a half million people [in the West bank] living without sovereignty,”

Uri Dromi, a retired air force colonel and former ally of Prime Minister Yitzhak Rabin who was assassinated in 1995, told me over lunch in Jerusalem. “You can’t risk being sucked into a colonial war. You Brits had it, the French had it – you always lose. What’s more important, the settlements or the survival of a democratic Jewish state? You can’t kick the people out. The Jordanian option [whereby the West Bank Palestinians would be absorbed into Jordan] is not viable. No, the real danger for Israel is to be disconnected from the world.

“That’s why a majority of Israelis now support two states. I see hope. But I don’t want the solution to be enforced on us rather than coming from another way. As things stand, we face another round of violence [in Gaza]. Things are happening the hard way.”

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Since his victory at the head of the Muslim Brotherhood in the Egyptian elections in June, President Mohammed Morsi has proved to be a flexible and pragmatic leader. “He’s not just a politician like Netanyahu, he’s a statesman,” Zomlot said.

Morsi and the Brotherhood exert considerable influence over Hamas yet Egypt remains an ally of the US, a relationship vital for a nation of 83 million people struggling with chronic problems: high unemployment, food and fuel shortages, a rapidly rising population. Despite unrest in the borderlands of the Sinai Peninsula, relations between Tel Aviv and Cairo remain stable and the two sides were engaged in talks about a ceasefire in Gaza throughout my stay in Israel.

The Israelis are under no illusions about the Brotherhood or Morsi. “We know what he really thinks of us,” a senior source told me. “But so far we have found him an honest broker. We are waiting to see the choices that are made.”

“Morsi can bring Hamas on board,” Husam Zomlot said, as he lit another cigarette. “He offers hope to us all. But Israel must understand this – what is happening in Gaza is not a war. War happens between two armies . . . war does not happen between a state and an occupied people. Call it murder, call it an assault, but don’t call it war.

“Gaza is not a free territory. It is the sole responsibility of the occupier to provide responsibility for the occupied.”

Yet not one Israeli to whom I spoke, from the left or the right, agreed with this. The message from inside Israel was one of profound and unyielding unity. “There can be no peace,” it is said, “until Hamas stops trying to kill us,” irrespective of the context in which Hamas acts or the suffering of the Palestinians inside Gaza.

When Netanyahu attacks Hamas and the jihadists, even as the death toll of children rises, he acts in the certainty that the people are with him, and on this issue will always be with him, or whoever succeeds him.

The endless war goes on.