For starters, there’s evidence that Trump’s rhetoric on the migrant caravan has resonated with his base. Republicans — especially Trump voters — were more likely than Democrats to have heard “a lot” about the caravan, and a majority of Republicans said the U.S. should “reject all of the immigrants in the caravan” (as opposed to accepting all of them or accepting only those who have a valid claim for asylum). Also, Trump’s dubious claim that the caravan contained “unknown Middle Easterners” (there have been no reports from intelligence agencies to suggest that this is true, and Trump later said he has no proof to support it) appears to have been widely believed by Republicans. Forty-seven percent said they thought that “some” of the people in the caravan were “Middle Eastern terrorists.” And 72 percent of Republicans said they “strongly approve” of Trump’s order to deploy thousands of troops to the border ahead of the caravan’s arrival.

Also in the YouGov poll, immigration was the most frequent response among Republicans when they were asked what the most important issue to them was; 20 percent chose it from a list of 15 issues (the economy ranked second, with 17 percent). Among independents, immigration came in second (13 percent said it was the most important issue to them) — which could be good news for Republicans looking to win among independents. (Among Democrats, immigration was tied for sixth place — their top answer was health care.)