Nothing’s going to stop this diplomatic fiasco from being implemented so it’s not worth asking whether Trump’s appearance at the rally will help or hurt the effort. Put it this way: His opposition will do no more to alienate Democrats who are on the fence than Dick Cheney’s will.

Let’s simply ask instead whether the participants will benefit politically. Cruz? Definitely. Trump? Sure. It’s a win/win. That’s the art of the deal.

Sen. Ted Cruz has invited fellow Republican presidential candidate Donald Trump to speak at a rally against the Iran nuclear agreement in Washington, according to the senator’s campaign.

The rally will be held at the Capitol and sponsored by Tea Party Patriots, Center for Security Policy, and the Zionist Organization of America, according to the campaign. The date, time and exact location haven’t been finalized.

Trump told reporters in South Carolina on Thursday afternoon that he and Cruz were planning an event protesting the deal in Washington. The Daily Beast previously reported that the two campaigns were mulling joint events, and the Washington Post reported that Cruz offered to take Trump on a tour of Texas’ border with Mexico.

Actually, the Daily Beast reported that Cruz was invited by Trump to join his photo op at the border, which is … odd. Everyone understands why Cruz has been hugging Trump, because he thinks he’ll inherit Trump’s anti-establishment voters eventually. According to a GOP strategist who’s “familiar with” Cruz’s thinking, “Cruz knows full well that Trump is a buffoon and is bad for conservatism. But he applauds him because it theoretically is good for Ted.” I’m not sure why Trump would hug Cruz back, though. Presumably he thinks he’ll pick up some of Cruz’s conservative credibility by association, but when Trump is asked about why he goes easy on Cruz, that’s not the reason he gives. What he says is that he’s nice to Cruz because Cruz is nice to him, a dim alpha-male approach to political alliances (i.e. “don’t mess with me or I’ll mess with you”). The smart play to impress conservatives who are leery of Trump would be to say that he admires Cruz for being the most staunchly conservative candidate in the race. Apart from Trump himself, of course.

Anyway. Everybody wins with the anti-Iran rally: Trump gets a chance to insert himself into the hottest policy debate in Washington while Cruz earns some more brownie points with Trump fans for having invited him to speak. He’s playing a long game here, counting on Trump to fade in due time as Republicans get serious about the race but in the meantime enjoying Trump’s ability to cut a path for populism through the primaries:

[A]s one Cruz adviser put it: “Without Trump in the race, we’d be having a nice debate over tax policy right now. Instead we’re talking about ‘anchor babies.'”…

The Cruz camp is confident that Trump’s candidacy will have a natural arc, that eventually political gravity will pull his numbers down, and that when it happens, Cruz will be ideally positioned to absorb his current supporters. In the meantime, Trump will sustain plenty of attacks from other opponents. And as an added bonus for Cruz’s hands-off approach, Trump is doing his dirty work. The real-estate mogul has been especially harsh lately on Scott Walker, long considered by Cruz’s camp to be their most direct competition in Iowa because of his appeal to both evangelicals and tea-partiers…

The senator has always envisioned consolidating the evangelical and tea-party wings of the GOP behind his campaign, armed with an uncompromising record on the core issues that appeal to both. Not only do Cruz allies believe Trump will struggle to convert admirers into voters; they think his record, once scrutinized, will repel those conservative voters currently supporting him.

They’re both already eyeing a confrontation down the road, though. Said Cruz to National Journal, with characteristic tact, “There will come a time as the campaign moves forward when [emphasizing] additional policy differences may well be merited. I don’t believe we’re in that phase of the campaign.” Said Trump to CNN, with characteristic bluntness, “I may have to [hit Cruz] if he starts getting really close. I may have to.”

Tell me one thing, though: Where’s the hard evidence that Ted Cruz is the second choice of Donald Trump voters? Is there a poll I missed showing Cruz picking up the lion’s share of Trump’s support if he drops out? It’s reasonable to assume that lots of Trump fans will migrate over to him because they’re the two most outspoken populists in the race, but apart from that (admittedly significant) similarity and its expression in their mutual border-hawkishness, they couldn’t be more different. Trump fans love that he’s famous for reasons besides politics, they love that he speaks without affectation, they love that he’s rich and can’t be bought by donors and lobbyists, and they seem perfectly comfortable with his moderate stances on various issues. Cruz is a Harvard Law egghead who’s spent three years in the Senate — the same presidential career track as Obama — and he always chooses his words with exquisite care. He’s raised a ton of money from the donor class and he’s a rock-ribbed conservative. Unless populism is the only quality you prize in your candidate of choice, there’s no reason to move from Trump to Cruz or vice versa. Granted, it wouldn’t be surprising if most tea partiers who prefer Trump shift to Cruz once Trump is done, but those people are just a decent-sized part of a decent-sized part of the total Trump coalition — enough to give Cruz a boost in post-Trump polling but probably not enough in itself, I’d bet, to propel him into first place. Show me a poll that says Cruz is overwhelmingly the second choice of Trump voters. I’m asking earnestly. Since it’s now conventional wisdom that Cruz stands to benefit most from Trump’s departure, we should probably take a second to confirm there’s a solid reason to believe that’s true.