Anthony Zurcher: Midterm carnage weakens Trump but he still wields power for now

For two years the president has displayed a vice-like grip on the Republican Party, keeping his partisan rank and file in Congress and across the US in line through a combination of political rewards and bare-knuckle threats.

Now, however, there are signs that his hold may be loosening.

Some Republicans have begun showing a willingness to criticise his decisions in a way few would dare even a few months ago. His own vice-president, JD Vance, penned a lengthy post on social media blaming the war in Iran that Trump launched with Israel for Tuesday's sweeping Republican defeat.

"If you'd like to argue it was worth it, that losing the Senate for the next six years was worth it, then do so," Vance wrote. "But everyone knows why we lost.