WISCONSIN — Wisconsin Republican U.S. Rep. Mike Gallagher continues to face intra-party criticism this week, after joining three fellow Republicans to essentially block the GOP-controlled House from impeaching Alejandro Mayorkas, the Department of Homeland Security secretary. 

"Congressman Gallagher does have a certain independent streak," said Anthony Chergosky, a professor of political science at the University of Wisconsin-La Crosse. "He is a reliable Republican on a lot of issues but he does deviate from the party in certain circumstances."

The Milwaukee Journal Sentinel Thursday reported that at least one Republican primary challenger to Gallagher is now waiting in the wings and getting support from Roger Stone, a former Donald Trump adviser

"This is a high-profile situation of someone splitting from their party," said Chergosky. "Republican voters care deeply about the issue of immigration and the issue of border security has continued to become a more prominent political issue."

Watch the full interview above.