North America 14 August 2020 To transform the US, the Democrats need to win the Senate Taking control of the upper chamber from the Republicans would give Joe Biden crucial legislative and patronage powers. Drew Angerer/Getty Images. Democratic presidential candidate Joe Biden and his running mate Kamala Harris arrive to deliver remarks at the Alexis Dupont High School on 12 August 2020. Sign UpGet the New Statesman's Morning Call email. Sign-up Nate Silver, still the most trusted voice in political forecasting, has released his presidential prediction: as of 12 August, it gives Joe Biden a 71 per cent chance of defeating Donald Trump. Our US correspondent Emily has taken a look at Biden’s chances in this week’s magazine, but it is clear the outlook is currently very good. The only qualification is time – that is what accounts for the vast majority of Trump’s remaining hopes in Silver’s model: the possibility that polls might change. If the election were held today, with polls as they are at present, Silver’s model would give Biden a 93 per cent chance of winning. This is unlike in 2016, when Silver gave Hillary Clinton only a 71 per cent chance on election day, as the polls were then much closer. But the presidential election is only one part of the decade-defining contest being held on 3 November. Elections are also being held for the whole of the House of Representatives and a third of the Senate. And it is these Senate elections that will define the tenor of Biden's presidency, should it happen. Democratic control of the House, which the party secured in 2018, appears to be assured. But in the Senate the party only holds 47 of 100 seats, and is set to lose one of them in Alabama, leaving it needing to gain four Republican-held seats. The Democrats are on course to pick up one in Arizona – the Democratic candidate is Mark Kelly, the husband of Gabby Giffords, the former congresswoman who was shot in 2011 – with another half-dozen seats considered to be “toss-ups” by the Cook Political Report. They need to win three of these to hold the Senate with 50 votes (should Biden win), as Biden’s vice-president (ie Kamala Harris) will cast the deciding vote. [see also: Kamala Harris: Biden’s VP pick is first woman of colour on a major party ticket] Can the Democrats win three of those six “toss-up” seats? On current polls: yes. They lead in a well-polled race in North Carolina, where the Republican incumbent Thom Tillis trails the Democrat candidate by 6.6 percentage points. The Republicans also trail in Colorado, where former Democratic governor Tom Hickenlooper is set to defeat Republican Cory Gardner, although the race has only been lightly polled. And Republicans are also set to lose in Maine, where Susan Collins – a long-time Republican enabler despite her claims to be a moderate (she was a crucial supporter of Judge Brett Kavanaugh during his 2018 Supreme Court confirmation hearings) – is set to be unseated by Sara Gideon, the Democratic candidate. All four July polls in the state put Gideon ahead by four or five points. If the Democrats can win these three seats – and hold on to their seats in Michigan and Minnesota, as expected – they will narrowly control the chamber, and needn't win in the other toss-up races: in Iowa, Montana and Georgia, all of which lean Republican. (Democrats are also unlikely to unseat Mitch McConnell in Kentucky, or Lindsey Graham in South Carolina.) [see also: US election swing states: Virginia is for… Democrats?] But every Senate seat that the Democrats win will be vital: with only 50 seats, the 50th Democratic senator, whose politics will be far to the right of Biden’s White House, will effectively control legislation in the US. Nevertheless, winning a 50th Senate seat will hand Biden three powers – executive action, legislative initiative and judicial appointment – rather than merely the first, which is all he will be left with if he only wins 49. The politics of the early 2020s will hang on that difference. A Biden victory will stop the carnage of the Trump presidency. But only with control of the Senate will the Democrats be able to move the US in another direction entirely. › The Belarus crisis is a test for Britain and the EU Harry Lambert is special correspondent of the New Statesman and writes long-reads for the magazine. He tweets at @harrytlambert and can be best reached via the One Great Read newsletter. Subscribe To stay on top of global affairs and enjoy even more international coverage subscribe for just £1 per month!