With Donald Trump heading for a five-state sweep today, his two top rivals have cut a deal that carries a whiff of desperation.

Just as Trump’s campaign is adjusting to the realities of delegate warfare, Ted Cruz and John Kasich are colluding—and yes, that’s the only honest word—to stop splitting the anti-Trump vote.

The agreement struck by their campaign aides is that Kasich will stop campaigning in Indiana, which votes next week, and Cruz won’t show up in Oregon and New Mexico.

The fact that the deal is hard to defend is evident in how the candidates responded when reporters got a crack at them.

Cruz pivoted away from whether this was a Hail Mary pass and, oddly, called Trump a “fringe candidate”—who just happens to be beating him by hundreds of delegates and a couple of million votes.

Kasich said the agreement was "not a big deal" and that he wants people in Indiana to vote for him; he just won’t be campaigning there because of limited resources. So if Kasich’s fans do what he is asking, it won’t help Cruz in Indiana.

Trump’s reaction? Sad!

“It is sad that two grown politicians have to collude against one person who has only been a politician for ten months in order to try and stop that person from getting the Republican nomination,” his campaign said. The statement said Cruz and Kasich are “puppets of donors and special interests,” adding: “Collusion is often illegal in many other industries and yet these two Washington insiders have had to revert to collusion in order to stay alive.”

The alliance between the Texas senator and Ohio governor merely makes explicit what had been obviously implicit: Neither one has a shot at a first-ballot victory, so their only hope is to stop Trump short of the magic 1,237 and peel off delegates on subsequent ballots.

There’s nothing inherently awful about two rivals dividing up states to derail a common enemy; I just question whether it will have much practical impact. The Cruz camp sees Indiana as one state where the senator can slow down the Trump express and is only trailing by 6 points in the latest Fox poll, as opposed to double digits.

But the media may be far more interested than actual voters. Are Republicans going to go along with strategic voting? If they like Kasich, would they vote for Cruz just because the governor isn’t holding rallies in their state? If they like Cruz, are they going to side with Kasich in Oregon and New Mexico for the same reason? I have my doubts. It's hard to imagine two candidates who are more different.

Trump, meanwhile, is trying to create the perception that this thing is over. In the wake of his New York landslide, and expected wins in Pennsylvania, Maryland, Delaware, Connecticut and Rhode Island, the media are certainly treating him as the likely nominee. By bringing on Paul Manafort, whose experience dates to the Ford-Reagan convention in 1976, he is taking seriously the grubby business of courting delegates under arcane state-by-state rules that Trump denounces as rigged.

Manafort came aboard too late to influence the last several caucuses, but is leading an effort to make sure more of those running for delegate are Trump loyalists who can’t be flipped before Cleveland. In New York, Manafort's emphasis on playing in each congressional district meant that Trump won not only 60 percent of the vote, but about 90 of the state’s 95 delegates.

The talk inside the Trump camp is about winning smart—that is, winning the popular vote but then not losing delegates after the fact to Cruz’s more organized ground operation.

In effect, you have to win twice—and Trump was a bit late to that game before hiring Manafort and now others from the much-derided Washington establishment.

The Cruz-Kasich alliance—could there be a running mate offer down the road?—may be the last shot for the #NeverTrump crowd. Cruz recently told Politico that “one of the greatest risks of a contested convention is, if you come out with a party fractured, it potentially makes you vulnerable going into the general election.”

But fracture is now his strategy--and the only sure way for the GOP to avoid it is for Trump to wrap things up before the convention in Kasich’s home state.

Howard Kurtz is a Fox News analyst and the host of "MediaBuzz" (Sundays 11 a.m. and 5 p.m. ET). He is the author of five books and is based in Washington. Follow him at @HowardKurtz. Click here for more information on Howard Kurtz.