Rule 40’s the one that says a candidate isn’t eligible for the nomination unless he’s won a majority of delegates in eight different states. Trump has already passed that threshold; Cruz, I believe, has done it in six states with a good shot to get to eight considering that Montana, South Dakota, and Nebraska — conservative strongholds — are all still to come and are winner-take-all. Kasich has done it in just one state, Ohio, and will finish the race having done it in just one state unless something very unusual happens over the next two and a half months. Simple question, then: What incentive do Trump and Cruz, and the vast majority of delegates at the convention who’ll favor one of the two of them, have to eliminate Rule 40? Why open up the universe of possible nominees to Kasich, or Paul Ryan or Mitt Romney, when they have the numbers to seal the process and force delegates to make a binary choice between the two of them? That’s especially important for Cruz, who’s drawing support from many establishmentarians right now because at the moment he’s the sole available alternative to nominating Trump. The instant he’s no longer the sole available alternative, which is what would happen at the convention if Rule 40 was eliminated, there’s no need for establishmentarians to stick with him. His strategy here, in other words, is eminently sensible. It may even be that the only way Cruz wins the nomination is if delegates, spooked by Trump’s toxic numbers in general-election polling, have to decide between him and Trump and no one else. Let a dark-horse candidate like Ryan into the mix and the delegates may decide that the party’s only shot at unity is to avoid choosing between Trump and Cruz and go with someone off the grid.

This is also further evidence that Cruz isn’t interested in any sort of anti-Trump alliance with Kasich — which, if you believe Kasich’s campaign, is on the table.

In a storyline that could be ripped from a House of Cards script, John Kasich’s campaign is looking to coordinate behind the scenes with Ted Cruz’s in a mutual effort to deny Donald Trump enough delegates to win the Republican presidential nomination. They even tried to get 2012 nominee Mitt Romney to help broker it.

The only problem for team Kasich is that Team Cruz is not interested.

Kasich adviser John Weaver told CNN that Romney urged Cruz campaign manager Jeff Roe to contact the Kasich campaign, but Roe has yet to do so.

Roe told CNN he did speak with Romney, but declined to disclose details of their private conversation. A Romney spokeswoman also declined to comment on discussions he has had with the campaigns.

What Roe did tell CNN was that the Cruz campaign has no desire to work with Kasich because they do not believe there is any advantage in it to the Texas senator.

Supposedly Team Cruz believes that Kasich is mainly pulling anti-Trump votes from Cruz, not votes from Trump, and therefore the sooner he can be forced out of the race, the better. I think that’s too cute by half, though: Certainly Kasich is a better play than Cruz in some moderate blue-state urban areas, which could be crucially important in California on June 7th in denying Trump the delegates he needs to clinch. (Remember, California is winner-take-all by congressional district. Kasich may be stronger than Cruz in key districts.) The deeper reason for Cruz wanting to push Kasich out ASAP may be the Rule 40 calculus I described above — namely, that the more delegates Kasich piles up, the more pressure there’ll be to make him eligible for the nomination as an alternative to Trump and Cruz. It may even be that Kasich, as part of the price for coordinating with Cruz, would demand that Cruz ask his delegates not to preserve Rule 40 at the convention. Imagine if Cruz agreed to that, he and Kasich successfully prevented Trump from clinching 1,237 delegates, Rule 40 was abandoned in Cleveland — and then Kasich ended up being chosen as nominee because he polls much better head-to-head against Hillary than Cruz or Trump does. Cruz may believe, not incorrectly, that only by forcing the party to choose between him and Trump exclusively is he the likely nominee.

Question, though: If Trump does fail to clinch a majority of delegates before the convention, what incentive does he have to ask his delegates to preserve Rule 40? Why shouldn’t he try to screw Cruz by asking them to get rid of the rule? If the nomination’s going to be “stolen” from Trump, he might as well do what he can to make it easier to “steal” it from Cruz too. He could even make some sort of deal with the RNC to oppose Rule 40, which would open the door to nominating someone besides Cruz on a second or third ballot, in exchange for greater influence over the convention, input on choosing the eventual nominee, and so on. A lot depends on Trump’s momentum over the last two months of primaries. If he’s slowing down and losing ground to Cruz, leaving him out of range of clinching on the first ballot, he may conclude that he has no real chance of being nominated and instead decide to negotiate. If he does have a real shot at clinching, obviously the calculus will be different.

Exit question: Should Cruz be attacking Kasich here for failing to “win at the ballot box”? That’s precisely the same argument Trump will throw in his face when Cruz eventually ends up arguing that the nominee should be a guy who didn’t win the most primaries.