“Democracy is at risk and this is your moment to defend it,” Joe Biden told voters today as Americans head to the polls for midterm elections, and the Democrats face an uphill struggle to retain control of Congress.

The US midterms, which fall in the middle of a president’s four-year term of office, are a vote to determine who gets a seat in both the House of Representatives and the Senate. They’re also seen as a vital test of the current president’s popularity – and one which will set the tone for the next two years in office.