Desperate times for the Republicans call for desperate measures. In any other situation, it is impossible to imagine figures such as Mitt Romney or Jeb Bush endorsing Ted Cruz as the party’s nominee. Yet they feel Donald Trump’s scorched earth advance leaves them no choice. They calculate that Mr Cruz is the only candidate left with a chance of stopping Mr Trump from winning a majority of delegates before the final primary in June.

With either as nominee, Republican leaders have all but written off hope of recapturing the White House. Going with Mr Cruz would at least enable them to keep their party intact, albeit at the risk of a third-party candidacy by an enraged Mr Trump. Lindsey Graham, the senator from South Carolina, likened it to a choice between being shot or poisoned. He too has swallowed the hemlock. Not one of Mr Cruz’s new allies believes he should be president, or that he would stand much chance of winning. They are playing a different game. For their party’s future, they would rather lose with Mr Cruz than with Mr Trump.

There is not much chance that the last minute ploy will work. With 29 states having already voted, Mr Trump has gathered about 60 per cent of the delegates he needs to push him over the top — the magic number is 1,237. If Mr Trump crossed that threshold, there would be no stopping him.