President Donald Trump on Thursday seized on a new migrant caravan approaching the US to frame the midterm elections as a fight over border security while blaming Democrats, without evidence, of supporting the influx.

“It’s going to be an election of the caravan,” Trump said at a campaign rally in Missoula, Montana. “You know what I’m talking about.”

In an extended riff about illegal immigration and the caravan, Trump told the crowd that Democrats were banking on the caravan to arrive before Election Day so they could vote for Democrats — even though as asylum-seekers, they wouldn’t be citizens and therefore would not be able to vote in the congressional elections.

“As you know, I’m willing to send the military to defend our southern border if necessary, all ’cause — because of the illegal immigration onslaught brought by the Democrats because they refuse to acknowledge or to change the laws,” he said. “They like it. They also figure everybody coming in is going to vote Democrat, you know. Hey, they’re not so stupid when you think about it, right?”

Trump has repeatedly accused the Democrats of wanting “open borders,” though he hasn’t provided evidence for that claim. Although Democrats typically call for more relaxed policies toward undocumented immigrants, major party officials still advocate for some measure of regulation and security at the border. President Barack Obama was dubbed the “deporter in chief” among some immigrant advocacy groups for steps his administration took, and more than 2.4 million people were deported during his administration.

Responding to Trump’s rally on Friday, Sen. Jeff Merkley, an Oregon Democrat, compared Obama’s efforts to assist Central America to stem illegal immigration to Trump’s actions.

“They almost want there to be an immigration challenge because they are looking for some way to create something to frighten the American people during an election,” Merkley told CNN’s John Berman “New Day.”

Trump slams US laws

Trump also claimed that “if a foot hits the ground” — if an undocumented immigrant sets foot on US soil — the US is powerless to deport them, even though his administration has aggressively sent thousands of undocumented immigrants back to their home countries.

“A foot hits the ground — you know, if a foot hits the ground, we’re not allowed to say ‘Hey, go back.’ Every other country in the world, they say go back. ‘Can’t come in, sorry.’ A foot hits the ground, we have to, by law, with these horrible people that are making their own rules having nothing to do with our Constitution,” Trump said, apparently referring to Democrats.

“We have to take those people in even if they are criminals. And we have hardened criminals coming in. You think those people are perfect? They’re not perfect. We have some bad people coming in, and by law, we have to take them in and then we have to — it’s called ‘catch and release,’ you ever hear this one?”

“Catch and release” refers to the fact that many undocumented immigrants end up living in the US for years because of a deeply backlogged immigration court system. When deportable immigrants are arrested, some go into mandatory detention but some must be released as the US can only physically detain about 40,000 immigrants at a time. Many immigrants deemed not to be flight risks and not dangerous have been released on their own recognizance or with monitoring technology.

Adding more immigration judges could alleviate the backlog, though Trump has questioned the process of immigrants going through the court system and has called for deportations without “judges or court cases.”

At one point Thursday, Trump said he was “taking full blame” for illegal immigration because he has “created such an incredible economy” that was attractive to non-citizens.

An election about ‘law and order’

This week, Trump, who has made combating illegal immigration a cornerstone of his political career, has pointed to the caravan making its way from Honduras as part of his efforts to galvanize Republicans ahead of the midterms.

He said Thursday the midterms represented “an election of (newly minted Supreme Court Justice Brett) Kavanaugh, the caravan, law and order, and common sense.”

“That’s what it’s going to be,” he said.

Trump has threatened on Twitter to cut money and aid to Honduras if the caravan was not “stopped and brought back” and has broadened his warnings to include other Central American nations as well.

The Honduran migrants, trekking in a caravan toward Mexico’s southern border, say they’re headed for the United States to flee violence and searching for economic opportunity. The US has leaned on Mexico to stop them before they reach the US border.