Senate Majority Leader Mitch McConnell (R-Ky.) reacts at a news conference on Capitol Hill on July 17. (J. Scott Applewhite/AP)

Senate Majority Leader Mitch McConnell sought to put pressure on Democrats on Tuesday on the issue of immigration, calling it “shocking” that some potential White House contenders are embracing calls to dismantle the federal immigration enforcement agency.

The remarks by McConnell (R-Ky.) suggest that Republicans will continue to seize on progressive activists’ slogan of “Abolish ICE” ahead of the November midterms, putting vulnerable red-state Democrats in a precarious spot.

Speaking with reporters at the Capitol, McConnell made note of protests in his hometown of Louisville, where demonstrators maintained an “Occupy ICE” encampment until a police crackdown last week.

McConnell and a protester who is a member of the Democratic Socialists of America have traded op-eds on the issue in the Louisville Courier-Journal in recent days, and McConnell said Tuesday that he believes “there are a lot of people in America now who don’t even remember socialism.”

“We thought it was kind of a relic on the ash heap of history decades ago,” he said, taking aim at the op-ed author’s call to eliminate international borders.

McConnell said that in his own letter, he “pointed out that ICE does very useful work” before going on to hammer Senate Democrats on the issue.

“What is I think doubly shocking is it seems that some of our colleagues in the Senate who have their eye on the White House seem to be adopting the view that we ought to get rid of ICE and therefore have no border security at all,” he said.

The future of the U.S. Immigration and Customs Enforcement agency, he added, will be “quite a significant issue” in the midterm elections and will “certainly affect how we go forward on immigration in the future.”

Some potential 2020 White House hopefuls, such as Sens. Elizabeth Warren (D-Mass.), Kamala D. Harris (D-Calif.), Kirsten Gillibrand (D-N.Y.) and Sen. Bernie Sanders (I-Vt.), have echoed calls from the left to abolish or reexamine ICE, arguing that the agency, which is charged with detaining and deporting undocumented immigrants, has been rife with abuses of power under the Trump administration.

Moderate Democrats, however, have struck a noticeably more cautious tone.

A Pew Research Center poll released Tuesday showed that public perceptions of ICE are starkly divided along partisan lines. Among Republicans and Republican-leaning independents, 72 percent view the agency favorably, while just 20 percent of Democrats and Democratic-leaning independents said the same.

That means that the issue is a thorny one for Senate Democrats such as Joe Manchin III (W.Va.), Heidi Heitkamp (N.D.), Joe Donnelly (Ind.) and Jon Tester (Mont.), who are facing tough reelection races in states that President Trump won by large margins in 2016. Manchin is already facing ads on the issue.

In a speech Tuesday afternoon at the Veterans of Foreign Wars national convention in Kansas City, Mo., Trump reprised his campaign-trail argument that Democrats who want to abolish ICE are weak on combating gang violence and illegal immigration. Congressional Democrats have supported funding for additional infrastructure and security at the border.

“And ICE — ICE. Oh, ICE. Thank goodness for ICE,” Trump said. “Democratic politicians want to abolish ICE. They want to see open borders. Can you imagine?”