A closed sign is posted on the gate of Smithsonian’s National Zoo on Wednesday in Washington. Smithsonian’s National Zoo is closed due to the partial government shutdown. Credit: Carolyn Kaster | AP

We’re now well into one of the longest government shutdowns in U.S. history. The problem this time? It has never made sense for President Donald Trump to force a shutdown over funding for his border wall. So assessing what will come next is, well, difficult.

As budget maven Stan Collender puts it in his own analysis: “this is Trump; logic won’t necessarily be the guiding force.” What Trump has been doing so far is, as political scientist Dave Hopkins points out, following the lead of the House Freedom Caucus.

But Freedom Caucus radicals don’t have plans for either policy gains or public-relations wins. What they care about is proving that they’re True Conservatives by differentiating themselves from mainstream Republicans. In practice, that means finding irrational but tough-sounding tactics to endorse.

That’s this shutdown in a nutshell.

Instead of making a deal last year, when Republicans held unified control of government, Trump has chosen to negotiate from a position of relative weakness as Democrats take over the House majority. What he’s bought for that trade-off is a very public demonstration of his belief in a border wall.

Trading policy gains for conservative credentials has never seemed like a very good deal for House members. In their defense, though, the radicals generally face bigger risks from primary challenges than from general elections, so their calculation at least has some logic to it.

The same can’t be said for the president.

Even when Bill Clinton and Barack Obama were judged by most observers to have won shutdown battles, with Congress taking most of the blame, their short-term approval ratings took a hit. This time Trump will likely take most of the blame; after all, he’s already claimed responsibility for it.

But the bigger problem for Trump is that he’s picking this fight during a dangerous period. The incentives for congressional Republicans to stick with him are already unusually low, and now he’s shutting down the government over a policy that few of them care about very much. At the same time, his foreign-policy decisions are angering many in his party and financial markets are in turmoil.

Collender is probably correct that Trump thinks he’s winning. Democrats certainly think they’re winning. That’s usually a formula for a very long standoff.

On the other hand, Trump is certainly capable of suddenly shifting gears and accepting an offer that undermines his allies on Capitol Hill — and, knowing that, congressional Republicans may well attempt to end this sooner rather than later.

Plus, as Congress scholar Sarah Binder points out, both Trump and the wall are unpopular, and that’s bound to put even more pressure on Republicans. As far as the Democrats go, my sense is that they have little interest in pressing their new negotiating advantages.

If they can get the deal that they had two weeks ago when the Senate passed a bill to keep the government open, they’ll take it. That’s the agreement that Trump had seemingly endorsed and then rejected — which gets back to where I started: It’s impossible to make predictions about this stuff when one negotiator behaves irrationally.

Jonathan Bernstein is a Bloomberg Opinion columnist covering politics and policy. He taught political science at the University of Texas at San Antonio and DePauw University, and wrote A Plain Blog About Politics.