President Trump’s decision to declare a national emergency to build a wall at the U.S.-Mexico border represents a last-ditch effort to do something that Congress refused to let him do — in the service of fulfilling a campaign promise to his base.

Among the broader public, though, it looks like an electoral loser.

A new NPR-PBS-Marist College poll was launched when Trump declared his national emergency four days ago. And the verdict isn’t a good one: The poll shows 61 percent of registered voters disapprove of Trump’s national emergency declaration, vs. 36 percent who approve of it.

The opposition spans nearly every demographic group. Of the more than 40 groups broken out by the poll, only Republicans (both men and women), Trump supporters, white evangelicals and rural voters don’t see opposition cresting 50 percent. (Rural voters, though, are split 47-47 — despite favoring Trump 61-34 in the 2016 election.)

Those numbers aren’t hugely surprising, given they track pretty closely with the popularity of the wall (generally around 35 to 40 percent approval) and with what polls showed on the idea of a national emergency (CNN showed 66 percent opposed before Trump declared it). The national emergency declaration is modestly more popular than in an automated HuffPost-YouGov survey this weekend (37 percent in support vs. 55 percent opposed), but that poll showed support for the wall more broadly at 45 percent. That’s higher than just about every poll in recent months — suggesting a possible outlier.

Perhaps more important in the Marist poll, though, is this question: “Does President Trump declaring a national emergency to build a wall along the U.S.-Mexico border make you more likely or less likely to vote for him for reelection in 2020?” On that question, a majority — 54 percent — says this is a motivator to vote against Trump, while just 33 percent say it’s more likely to make them vote for Trump.

The utility of this question is up for debate. Oftentimes it breaks down like the broader question, and that’s certainly the case here. But it can also give us insight into whether the opposition is inflated by people who simply don’t care all that much — and whether Trump might even reap a bigger benefit by motivating his base.

But that doesn’t seem to be the case here — at least judging from this one poll. Here are some comparisons between how key 2016 groups voted then and how they say this decision affects their vote in 2020:

  • Non-college-educated white men: supported Trump 71-23 percent, but this makes them less likely to support him, 47-41 percent.
  • Independents: backed Trump 46-42 percent but say this makes them less likely to support him, 55-29 percent.
  • Midwest: Trump’s most important region (most notably wins in blue-leaning Michigan and Wisconsin) says this alienates them, 54-34 percent.

Much has yet to play out in this debate, most importantly in the legal fight that has already gotten off the ground. But we have now been fighting about this for the better part of two months — since before the 35-day government shutdown. That suggests views of it are pretty hardened, in a way that isn’t helpful for Trump.

Perhaps Trump reasoned he needed to do this anyway because he can’t survive without his base — that he made a promise and he’d be sunk if he doesn’t do everything he can to try to fulfill it. But just because something might have been the best option doesn’t make it a good one. This is a choice that is surprisingly unpopular with the groups that were vital to his 2016 win.