US midterms Control of congress and democracy on the line

This is the first election since the January 6th raid on Capitol Hill last year. It reminds America and the world just how fragile this powerful democracy can be.

Once again the president's party is likely to lose its hold on the House. It happened to Bill Clinton, George W Bush, Barack Obama and Donald Trump.

The benign view is that this creates a divided government, clipping a president's wings. But it also grinds government to a halt and in an increasingly toxic and tribal landscape it could unleash a flurry of investigations and impeachments,

More than 40 million Americans have already cast their ballots early - and millions more are heading to the polls today.

All 435 seats in the House of Representatives are on the ballot - where the Democrats face an uphill battle to hang onto control, as well just over a third of the 100 Senate seats.

It's on a knife edge - the Republicans need to gain just one seat to take control there. Americans in 36 states are also electing governors - as well as numerous city mayors and state legislatures.

One of the tightest Senate races is in the southern state of Georgia.