Kind of humiliating for Bernie now that he’s formally accepted, no? “Sure, I’ll debate.” “Me too!” “Psych.”

I think this is a mistake by Trump, for what it’s worth.

Two months ago, the first time the idea of a Trump/Sanders debate was floated, I thought it would have been nuts for Trump to even consider it. He had nothing to gain by it and lots to lose if Sanders used the forum to successfully expose his economic populism as an inch deep. Ed argued this morning that it still makes no sense for Trump to want this debate while it makes lots of sense for Sanders to want it since Sanders, not Trump, has everything to gain.

I disagree. I’d look at it in terms of what each of them has to lose. Now that Trump is safely past the primaries, what does he have to lose by sharing a stage with Bernie? He’s eager to pander to Sanders’s audience on trade; a joint forum with mega-ratings gives him the opportunity to do that. He also wants to broadcast his message that “the system is rigged” to Bernie fans, who are feeling more receptive to that message than ever given Hillary’s big lead with Democratic superdelegates. Trump’s approach at a debate with Sanders would be pure sweetness, flattering him for his populism and trying to enlist him as a de facto ally in their shared belief that Hillary Clinton is simply awful. He’d probably half-jokingly offer Sanders the bottom of the ticket. A debate with Bernie is a direct pipeline to the independents and lefties Trump is hoping to convert to his cause. Even if he does come off as having barely any idea of what he’s talking about on policy, plenty of anti-Hillary voters won’t care. The “system is rigged” rhetoric has a strong pull on people, and Hillary Clinton is the system. Bernie would be hard-pressed to disagree.

Meanwhile, on Sanders’s end, what does he gain by debating Trump? He gets another night in a big media spotlight before the primaries end, and then … what? The delegate math is what it is; Hillary’s going to be the nominee. Spending an hour arguing with Trump won’t change that. He’d gain a big audience for an evening to broadcast his socialist message, but he’s destined to have that anyway in July when he inevitably lands a showcase speaking slot at the convention. Meanwhile, by bigfooting Hillary and stepping into the role of Democratic debate partner for the presumptive GOP nominee, he’s going to piss off a lot of Democrats, especially if Trump manages to use the debate to maneuver Bernie into agreeing with him about some aspect(s) of Hillary’s awfulness. And those pissed-off Democrats won’t just be stalwart Hillary fans and establishment Democrats, whose opinions don’t matter to Sanders. There are bound to be members of his own coalition who, despite being disappointed by the primary, are already reconciling themselves to backing Clinton in the name of defeating Trump. Sanders agreeing to play a supporting role in what would mainly be a Trump media stunt aimed at peeling off swing voters wouldn’t sit well with them.

And what about Bernie himself? However much he may dislike Hillary, I’m assuming he’d prefer to see her elected, not Trump. They’re closer on policy than he and Trump are and Bernie voters would have more leverage over President Clinton than they would over President Trump. If Bernie’s destined to become part of the “elect Clinton” effort, doing Trump a solid by agreeing to a stunt debate at a moment when his own chances at the nomination have passed seems bizarre.

And yet:

Bernie Sanders’s campaign is serious about debating Donald Trump and pressuring the likely GOP nominee to follow through on remarks he made to a late-night talk show host…

Sanders spokesman [Michael] Briggs had a curt reply when asked whether he thought the DNC would sanction a Trump-Sanders debate.

“Who cares?” he asked.

“They’re irrelevant to this process,” he added. “And anyway, the DNC doesn’t want debates.”

Maybe the sheer anti-Clinton butthurt within Team Sanders is overriding their better judgment. Or maybe … Bernie’s planning to sabotage Trump by making the case at the debate that any Democrat, Hillary Clinton included, is better than Trump? I don’t think that would faze Trump; Republicans have said worse things to him at the primary debates, and he’d know going in that he’s bound to take some flak from Sanders as the price of his opportunity to address Sanders’s audience directly. That’s the only way this makes sense to me strategically from Bernie’s perspective, though — as a chance to strike a blow for party unity by making a #NeverTrump argument on Hillary’s behalf. But given the tenor of Briggs’s comments above, it doesn’t sound like that’s what he has in mind.