JD Vance, Ron DeSantis and Ted Cruz all pointed to Iran war and affordability as key factors in Democratic victory

• Q&A: Ask your questions about Democrats’ win in the midterms

Republican hopefuls in the race to succeed Donald Trump swiftly blamed two key pillars of his agenda – the Iran war and tariffs – for summoning the Democratic blue wave that swept the US midterm elections.

The fallout from the stunning success of Democrats on Tuesday night has left Republicans reeling – and grasping for the reasons behind the collapse in support. On Thursday, the Associated Press called more competitive House races for the Democrats, though Senate races in Alaska and Mississippi remained undecided.

Guardian analysis shows how tumbling approval ratings may have hurt candidates backed by US president

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• Send us your questions about the US midterms results and Democrats’ ‘blue wave’

Dozens of Republican candidates directly endorsed by Donald Trump lost their US midterm election races, according to analysis by the Guardian, raising questions over the power of the president’s support.

In past elections, Trump’s endorsements have been coveted. In the final stages of this year’s campaign, he actively urged voters to act as though he were on the ballot.