The senator said he would "not support and will not vote to use the military in our cities," adding that he thinks "it's a terrible image."

Paul warned the mayor that his resistance could be taken to the Supreme Court, where he could potentially be removed from office.

Sen. Rand Paul suggested that Denver Mayor Mike Johnston's pledge to resist Donald Trump's effort to deport illegal immigrants would be "a form of insurrection," during an interview Sunday on CBS's "Face The Nation.