Johnston is one of several mayors who have stated they will not assist the incoming Trump administration with its deportation plan, stating that Denver would “continue to be a welcoming, open, big-hearted city.” Paul, who has expressed criticism of Trump’s plan to use the Army to carry out his deportation plan, warned the mayor that his resistance could be taken to the Supreme Court, where he could potentially be removed from office.

“I don’t know whether or not there would be a criminal prosecution for someone resisting federal law, but he will lose, and people need to realize that what he is offering is a form of insurrection where the states resist the federal government,” Paul said on CBS News’s Face the Nation. “Most people objected to that and rejected that long ago. So I think the mayor of Denver is on the wrong side of history, and really, I think, will face legal ramifications if he doesn’t obey the federal law.”

In regards to how Trump could implement its deportation plan, Paul suggested he instead utilize the FBI, the Border Patrol, or the U.S. Immigration and Customs Enforcement. He also said using the Army is unlawful for this plan, and that there is “a better way” to carry it out.

Earlier this week, Paul warned against using the military to deport illegal immigrants because it would be a “terrible image,” as well as being illegal “for over 100 years to bring the Army into our cities.”

When asked if he would oppose voting to confirm Gov. Kristi Noem (R-SD) as Trump’s secretary of homeland security, Paul reiterated that he would not vote to use the nation’s military for an illegal immigrant roundup.

Gov. Greg Abbott (R-TX) warned Democratic lawmakers planning to oppose Trump’s mass deportations risk further losses at the ballot box, suggesting the party is “doubling down” on why it lost the presidential election. He added that voters are “angry” about how much illegal immigration is affecting the nation, and that voters have demanded for their government to take a stand against it.