AWFULLY late in the day, the Republicans are trying to unpick one of the collective action problems that are threatening to gift their nomination to Donald Trump. Thus, on April 24th, the non-aggression pact announced by Ted Cruz and John Kasich, his two surviving opponents, to cover three upcoming primaries. Under its terms, Mr Kasich will cease campaigning in Indiana, where Mr Cruz has a decent chance of winning many of the 57 delegates on offer. The senator from Texas will do Mr Kasich the same service in New Mexico and Oregon, which have 52 delegates up for grabs between them and enough moderate voters to give the governor of Ohio a hope of adding to his puny total of 148 delegates—which is 696 fewer than Mr Trump has.

The arrangement is borne of two different sorts of exigency. Mr Kasich is running out of cash; recent accounts suggested he had less than a million dollars to spend. More important, the pact starts with a straightforward recognition that, because neither challenger can win the 1,237 delegates needed to win the nomination ahead of the Republican National Convention in July, the best they can hope for is to block Mr Trump, and hope to horse-trade their way to victory at the convention.

Most delegates to the convention will be obliged to vote in line with their respective state primary and caucus results on the first ballot; Mr Cruz hopes to win the nomination on a second ballot, for which many delegates will be free to vote for the candidate of their choice. That is a realistic possibility, given his success hitherto in shoe-horning his supporters onto state delegate rosters. Mr Kasich’s vaguer hope is that Mr Cruz would also fail to muster a majority, on a second and subsequent ballots, leaving him an opportunity to emerge as a unifying figure. Given how badly the governor of Ohio’s moderate message has gone down with most Republican voters, that seems unrealistic. In the scenario Mr Kasich is hoping for, it seems as likely a non-runner, such as Paul Ryan, the speaker of the House of Representatives, would be inserted into the race.

Had Mr Trump’s rivals ganged up against him earlier in the contest, he might not be the front-runner. The fact that Republican field was crowded—by 17 candidates early on—fractured what might be loosely described as an establishment, or anti-Trump, vote; that allowed Mr Trump to surge to preeminence with around a third of the total vote. He easily won the New Hampshire primary with 35%; his more moderate rivals—Mr Kasich, Jeb Bush, Marco Rubio, Chris Christie and Carly Fiorina—won 49% between them. But will Mr Cruz’s and Mr Kasich’s attempted stitch-up work now?

It seems unlikely to harm them; even if Mr Trump has naturally attempted to rally his supporters against what he described as their “collusion”. He greeted it with this tweet: “Wow, just announced that Lyin’ Ted and Kasich are going to collude in order to keep me from getting the Republican nomination. DESPERATION!” In Indiana, in particular, the outcome could easily be swayed by a reapportioning of the 19% of the vote Mr Kasich is currently polling. If more of it went to Mr Cruz, who has 33%, than Mr Trump, who has 39%, the Texan could win.

Given that the winner will take most of the state’s delegates, that could hurt Mr Trump badly. He has less to fear in Oregon and New Mexico, which share out their delegates in proportion to their vote. Provided Mr Trump’s vote-share did not actually fall as a result of his rivals’ deal, he would be unaffected by his rivals’ scheme.

Even in Indiana, however, the success of the deal will depend on it sticking. And on April 25th Mr Kasich raised some doubt about that, by insisting he still wanted his supporters there to vote for him. Mr Trump response on Twitter was swift and predictable. “Typical politician – can’t make a deal work”.