Jeb Bush can’t win Iowa. But he wants to make sure Marco Rubio doesn’t come close.

Jeb Bush has virtually no chance of winning the Iowa caucuses — but his team wants to make sure Marco Rubio doesn’t do too well there either.

On Tuesday, the Bush-allied Super PAC Right to Rise USA released a new negative ad attacking Rubio — and, according to the Des Moines Register’s Jennifer Jacobs, the ad will air on Iowa television.

The ad itself is a pretty misleading attack on Rubio for missing a Senate briefing on terrorism to fundraise (Rubio actually attended a similar briefing days earlier, one that included classified information).

What is interesting about the ad, though, is that Bush’s team is airing this attack on Rubio in Iowa, a state Bush himself has basically already conceded, rather than just focusing on New Hampshire, a state Bush desperately hopes to win.

But this move by Bush actually makes a lot of sense — because any good news for Rubio out of Iowa would be terrible for Jeb Bush.

The most recent polls of New Hampshire show Donald Trump in first place, and five candidates (Bush, Rubio, Chris Christie, John Kasich, and Ted Cruz) within a few points of each other in second place. Four of those five candidates (all but Cruz) are viewed as friendly to the GOP establishment, and therefore in direct competition with each other. This is why Bush’s allies have long been obsessed with stopping Rubio, and why Christie has recently started to trash Rubio on the campaign trail.

In Iowa, though, the most recent polls show Rubio as the top-performing establishment-friendly candidate, all by his lonesome. (He’s in third overall, behind Cruz and Trump, and just ahead of Ben Carson.) And, crucially, Iowa goes first, and its results can shake up the New Hampshire contest.

If Rubio does finish in third in Iowa, he wouldn’t get very many delegates. But he could get a lot of positive media coverage in the eight days between the caucuses and the New Hampshire primary. And it’s possible that Rubio could even end up doing better than third in Iowa. It doesn’t seem likely that he’ll win the caucuses, but he gets very high favorability ratings in the state, and there have been late, wild polling swings in previous Iowa contests.

Overall, any Iowa finish placing Rubio solidly above his mainstream Republican rivals will help him make the case that he is the candidate who can best stop Trump and Cruz and save the Republican Party — and that Jeb Bush isn’t. And a strong performance in Iowa by Rubio could swing New Hampshire voters, and the GOP establishment generally, towards him, as they’ll grow more likely to think he can win.

So the story Bush’s team desperately wants to see the morning after the Iowa caucuses is a story about how Marco Rubio underperformed there. They want the eight days before New Hampshire to be a story of Rubio’s failure and Cruz or Trump’s triumph. Then, they hope, Bush can ride to the rescue of the party by performing strongly in New Hampshire.

Naturally, then, Team Bush is trying to bring this outcome about by airing attack ads on Rubio in Iowa, to depress his support there. Ad spending hasn’t seemed to affect the race very much so far, but the vast majority of ads to this point have been positive ads. So Bush’s operation is hoping that some good, old-fashioned negativity can bring Rubio back to earth.