1 Cameron lost the loyalty of the right when he didn't win the general election outright
Conservative MPs have worried about Team David Cameron's electoral strategy ever since he became leader in 2005. Before the election, they were especially concerned about the lack of a clear message and about George Osborne's unpopularity. They could not understand why the Liberal Democrats were given equal status in the televised debates. They told Conservative HQ that the "big society" message needed to be more "doorstep-friendly". The Tory leadership's answer to every criticism of strategy was to look at the opinion polls. "Trust us, we're more than 10 per cent ahead," they said.
By election time, the lead shrank and a majority never came. Cameron's failure to win an election against a divided government, presiding over a deep recession and led by a prime minister whom 100 political academics have just rated the third worst since 1945, means he will never again get the same benefit of the doubt from Conservative members.
He compounded his problems with the party by trying to end backbench control of the 1922 Committee. The committee had been a thorn in John Major's side throughout the early 1990s; the former premier apparently advised Cameron to neutralise it. Cameron was forced to retreat in the face of anger and, in protest, MPs voted for the independent-minded Graham Brady as their new shop steward.
A great leader needs a wide range of qualities. We know that Cameron is brave, media- friendly and intelligent. But party management is also an important skill. Tony Blair, Margaret Thatcher and even Gordon Brown were good at the courtesies that are essential, if not sufficient, for harmonious parties. When she'd completed her red boxes, late into the night, Thatcher turned to a list of people who, at her insistence, her advisers had recommended deserved a handwritten note.
Cameron needs to improve this aspect of his leadership style. Few if any of the 37 Tory frontbenchers who did not make it into government because of the election result received any communication from him. Three months into his premiership, he hasn't spoken even one word to some of the MPs he didn't make ministers.
2 Cameron seized victory from defeat with his bold coalition deal
If failing to win a majority was his great failure, his boldness on the day after the election was Cameron's great success. He saw the potential in a "change alliance" of the kind that the blogger Guido Fawkes and the think tank head Mark Littlewood had long advocated. He made a "comprehensive offer" to Nick Clegg to form a coalition government that has the potential to change British politics for ever. Appointing a Liberal Democrat to nearly every Whitehall department did two things, one Downing Street insider told me: "It bound Clegg to every tough decision but it also minimised the number of Liberal Democrats who would be outside the tent, pissing in."
The emphasis he had placed as Tory leader on gay rights, civil liberties, climate change and fighting poverty may not have won the election, but it made the Con-Lib deal possible. The offer of a referendum on AV turned the deal from possible to done. Controversy still surrounds the events leading up to that event. Cameron led Tory MPs to believe that he needed to match an offer that Labour had made. Those MPs have subsequently learned that Labour made no such offer. At best, Team Cameron can be accused of not asking enough questions to establish the truth and, at worst, of misleading Conservative backbenchers.
3 In the handling of David Laws's resignation, the two parties bonded
Few early events in the government did more to build trust between the blue and yellow halves of the coalition than the handling of the revelations about David Laws's living arrangements. Over the 24 hours from when the story broke to when the then chief secretary to the Treasury resigned, it was impossible to know which aides were Tory and which were Liberal Democrats. The Downing Street teams almost became one in that moment, every member batting hard for their embattled colleague.
The Prime Minister's warm letter to Laws, accepting his resignation but hoping that he'd make a speedy return, was the culmination of a period that cemented the Clegg-Cameron-Osborne alliance. The overwhelming sense that I get from talking to Tory frontbenchers is that their Liberal Democrat ministerial colleagues are acting as one of the team and are being treated as such. The closeness means that, in reality, there are three parts of the coalition: 1) the almost indistinguishable front benches; 2) the Tory right; 3) the left of the Liberal Democrats who, in their hearts, would still have preferred a deal with Labour.
4 A decision to send inexperienced ministers into unfriendly departments with fewer political advisers
During the opposition years, Cameron made the decision to reduce the number of ministerial special advisers (SpAds). Under Labour there was a suspicion that SpAds had morphed into spin doctors and were an unnecessary burden on the stretched public purse. Remember Jo Moore, who worked for Stephen Byers, and her advice "to get out anything we want to bury" on the day of the 11 September 2001 attacks?
Cameron could and should have revisited this pledge when he and Clegg were junking other manifesto promises. For the sake of two or three million pounds a troop of extra SpAds would have reinforced ministers' attempts to master their departments. The cap on SpAds means inexperienced ministers are having to make historically unprecedented cuts with a bureaucracy that is itself being cut.
Even Cameron has been the victim of this policy and has been unable to appoint some key allies to strengthen his Downing Street operation, although some are being shoehorned into civil service roles. Don't be surprised if this policy is "updated" next month.
5 The appointment of Iain Duncan Smith to think the unthinkable on welfare
Cameron made many fascinating appointments but none was more surprising than the return of Iain Duncan Smith to the front line of politics. Many feared that IDS could not tame the sprawling Department for Work and Pensions, but anyone who has paid any attention to his years in the political wilderness couldn't question his missionary commitment to fight the war on poverty in bold new ways.
George Osborne may not have read the report on overhauling the benefits system that the Centre for Social Justice produced when IDS was its chairman, but it was not exactly a secret that this was the former Tory leader's agenda. IDS has formed an unlikely alliance with Clegg to design a benefits system that rewards low-paid workers. The Deputy Prime Minister, spurred on by his key adviser Richard Reeves, the former head of Demos, may be decisive if IDS is to overcome resistance from Osborne's Treasury in what may become a bloodier battle than the other great blue-on-blue conflict - between the Defence Secretary, Liam Fox, and No 11 Downing Street.
6 The Osborne Budget that did not restructure the tax system
George Osborne won much acclaim from Tory MPs and the right-wing press for his "emergency" Budget. The scale of his deficit reduction plan was certainly ambitious and, because of his candour and boldness, he was voted the country's most popular ever chancellor by one pollster. Over time, however, as the drip, drip, drip of spending cuts has become apparent, approval of the coalition has declined.
Missing from Osborne's Budget was a major plan for growth. The scale of the economic crisis demanded a more profound restructuring of the tax system. Osborne should, for example, have raised "sin taxes" (on pollution, expensive housing and fatty foods) in order to fund lower taxes on jobs and investment. Becoming the party that redistributes from the unproductive to the productive can still be a coalition objective, but if Osborne hasn't acted by the autumn it will probably be too late.
7 The backlash against Michael Gove's cuts is a sign of the unpopularity to come
Michael Gove was widely regarded as one of the Tories' fastest-rising stars when he became Education Secretary, but the man who was an excellent newspaper columnist and innovative thought-leader in opposition proves yet again that a very specific set of skills is needed to deliver a programme in government. The backlash to his bungled announcement of cuts to Labour's bloated school-building programme was a warning to every member of the coalition that public opinion is likely to be far less forgiving when the detail of spending cuts is finally revealed in the autumn.
8 Andrew Lansley's pledge to reform the National Health Service confirms the coalition's hyperactivity
Tory radicals worried that Cameron would be another Blair and that he would minimise the policy reforms that might jeopardise his re-election. David Davis may have called it the "Brokeback Coalition" but, say others, the government looks more like a "breakneck coalition". It is advancing at speed on multiple fronts. Reform of schools, policing and local government was expected. Big cuts to spending were unavoidable. More interesting has been the unexpectedly ambitious proposed reforms to the NHS and the welfare state. Andrew Lansley's conversion to proposing a sweeping reorganisation of the NHS is perhaps the most surprising. The Health Secretary was regarded as the epitome of caution in opposition, but his unexpected pledge to replace English primary care trusts (PCTs still featured in May's coalition agreement) adds another ball to Cameron's extraordinary juggling act.
9 The decision to reverse the Conservatives' prison-building programme
Although the coalition starts with a programme of reforms that should delight every Conservative, the trajectory of the coalition is clear: it is heading leftwards or it is heading for breakdown. The Liberal Democrats have lost so many of their left-wing voters that Cameron has to give them concessions that will prevent defections of MPs and big losses in next year's Scottish, Welsh and municipal elections. Ultimately this may include a non-aggression pact whereby Tory candidates won't threaten vulnerable Liberal Democrat incumbents.
The policy concession that may cause most problems for the Tories isn't Trident or Europe (where backsliding has been marked), but the much more earthy decision to go into reverse gear on prison policy. To be fair to the Tories, the policy is as much Ken Clarke's as it is the Liberal Democrats', but anger stretches from Michael Howard in the House of Lords to the Daily Mail and even the Sun on Fleet Street. You can be sure that the Mail will splash-headline any crime committed by someone they think would have been in jail if the Tory manifesto pledge on prison-building had been executed.
10 Cameron's decision to work shorter hours than his predecessors
If you are a Conservative leader, the highest accolade is to be elevated to a position alongside Margaret Thatcher or Winston Churchill. Cameron may have been in Downing Street barely three months, but the new Prime Minister was recently introduced to readers of the New York Times as being more ambitious than the Iron Lady. Even colleagues are making the comparison. But if the Cameron government is to match Thatcher's ambition, it also needs her work ethic.
Blair talked of the scars on his back sustained through trying to reform Britain's public services. Effective reform is only 10 per cent inspiration, but 90 per cent perspiration.
Will Cameron have the Thatcher-like resilience to survive the bureaucratic backlash that awaits his government when the cuts start to bite? Will he have Thatcher's work ethic, either? She spent most evenings working on government papers and her family life suffered because of it.
Cameron, it seems, doesn't arrive at his desk in No 10 until 8.30am and has left by 7pm. Away from that desk, he may be working privately, but he certainly finishes earlier than his Downing Street predecessors. An inattention to detail has long worried some of his aides. A failure to master briefs was evident in the election debates and also in his accurate but ill-chosen remarks about Pakistan. It's not enough to get the big judgements right if you get the details wrong. Government really is that unforgiving.
Tim Montgomerie is the editor of ConservativeHome.