"I think a lot of people, including myself, were attracted to the president because of his reticence to get us involved in foreign war," Paul said.

Over the last few months, Trump has launched a campaign to eliminate alleged drug trafficking in international waters near Central and South America, mostly through controversial boat strikes -- although he has also floated the idea of taking the strikes to land.

On Monday, the Trump administration will officially designate Venezuela's Cartel de los Soles as a foreign terrorist organization -- a decision Paul on Sunday criticized.

"I think by doing this, they are pretending as if we are at war," said Paul, chair of the Senate Committee on Homeland Security and Governmental Affairs.