Marco Rubio and John Kasich are both in danger of losing to Donald Trump in their home states on Tuesday.

So on Friday morning, Rubio spokesperson Alex Conant made an unusual appeal during a CNN appearance — that Republicans should vote for Kasich in Ohio.

"If you are a Republican primary voter in Ohio and you want to defeat Donald Trump, your best chance in Ohio is John Kasich," Conant said. He added, naturally, that the best chance to stop Trump in Florida would be by voting for Rubio.

This has of course been obvious to anyone looking at recent Ohio polls, but it's still quite odd for one presidential candidate to advocate voting for another. Many quickly wondered whether Kasich would reciprocate, and conservative commentator Erick Erickson speculatively proclaimed that he thought a "deal" had been struck among the non-Trump candidates. Indeed, Rubio seemed to be following a plan laid out by Mitt Romney last week, in which he urged Republicans to vote for whomever could best beat Trump in each state.

But just minutes later, Kasich made very clear that he isn't on board, when his spokesperson blasted Rubio with this brutal takedown:

Kasich spox Rob Nichols on Rubio news: "We were going to win in OH without his help, just as he's going to lose in FL w/o ours" — Kathleen Ronayne (@kronayne) March 11, 2016

Kasich won't accept this deal, because he wants Rubio out of the race

Kasich has developed of a reputation of being the above-the-fray, nice-guy candidate lately, so the tone of this statement is rather striking. But when you think about the Kasich campaign's strategy at this point, it actually makes a great deal of sense — even though it could end up helping Trump.

Of late, the Ohio governor has openly acknowledged that he is too far behind to win a delegate majority — and that he's instead positioning himself for a contested convention. "No one is going to have the numbers," he said on ABC earlier this week.

But even if that convention does happen, Kasich won't be particularly well-positioned there unless he starts winning a lot more delegates:

Yet he may have some reason to hope. The South, a region where he's been particularly weak, is practically done voting. And many big Northeastern, Midwestern, and West Coast states — states where a mainstream alternative to Trump and Cruz could catch on — haven't yet voted. So Kasich is still hoping he could be that mainstream alternative, pick up lots of delegates, and become a serious player at a contested convention.

To make that happen, he wants Rubio — his only remaining mainstream-friendly rival — out of the race. If Rubio wins Florida, though, he has a pretext to stay in the race. So Kasich has no desire to help him do that.

Indeed, though both Rubio and Kasich's campaigns are in awful positions right now, Rubio appears worse off despite his bigger delegate lead. According to recent polls and state results, Rubio's campaign is in free fall and Kasich's is actually on a bit of an upswing. And polls show Rubio down much further to Trump in Florida than Kasich is in Ohio (indeed, Kasich even led the most recent Ohio poll).

So, far from being an altruistic effort to stop Trump, this gesture by Rubio smacks of desperation. Kasich has spurned it because he feels he's in a stronger position than Rubio is.

The problem, of course, is that ceding Florida and its 99 winner-take-all delegates to Trump makes it more likely that the billionaire will win that outright majority of delegates and avoid a contested convention altogether. So Kasich is playing a dangerous game. In his attempts to become the last "reasonable" man standing, he could well help deliver the nomination to Trump.