Delirious supporters for Mr Romney gathered in a ballroom here in Novi, Michigan, northwest of Detroit to celebrate his victory over Rick Santorum in the state by a nonetheless slim margin of only 41 per cent to 38 per cent with most votes counted. It may get his campaign back on track and should damp down party chatter that his candidacy was coming apart at the seams under pressure from the more conservative Mr Santorum.

Mr Romney also handily pocketed Arizona, an important state in the general election and a testing aground of his appeal in the sun belt of America.  With nearly all precincts reporting, he had 48 per cent of the vote there to 26 per cent for Mr Santorum.  Newt Gingrich and Ron Paul were left trailing the two leaders badly in both states.

Here in Michigan Mr Romney overcame what had been a wide deficit in the opinion polls. “It was just a week ago that they were ready to count us out,” Mr Romney said of the “pundits and pollsters”.  He made fleeting reference to the slimness of his win but declared, “We didn’t win by a lot but we won by enough and that’s all that counts.”