Setting the stage for what is sure to be interesting Republican intra-party infighting over the 2016 presidential nomination, Sen. Rand Paul on Friday launched a number of social media counterattacks at Sen. Marco Rubio over comments he made Thursday about Cuba.

It started with a comment made Thursday by Paul in a radio interview with Tom Roten of News Talk 800 in West Virginia, in which Paul said the 50-year Cuban embargo "just hasn't worked" and normalizing relationships is "probably a good idea," a position that differs from many of his libertarian-leaning counterparts.

"If the goal is regime change, it sure doesn't seem to be working and probably it punishes the people more than the regime because the regime can blame the embargo for hardship," Paul continued.

In disagreement with Paul, Rubio commented on Fox News that Paul "has no idea what he's talking about," because the reason the embargo hasn't worked, according to Rubio, is that it "has a bunch of holes in it." Rubio continued by saying that it isn't the embargo hurting the Cuban people, it's the "lack of freedom and the lack of competent leaders."

Paul, the Senator who may have been called an isolationist more than any other current lawmaker, shot back through Facebook on Friday with this message:

"Senator Marco Rubio believes the embargo against Cuba has been ineffective, yet he wants to continue perpetuating failed policies. After 50 years of conflict, why not try a new approach? The United States trades and engages with other communist nations, such as China and Vietnam. Why not Cuba? I am a proponent of peace through commerce, and I believe engaging Cuba can lead to positive change.

"Seems to me, Senator Rubio is acting like an isolationist who wants to retreat to our borders and perhaps build a moat. I reject this isolationism. Finally, let's be clear that Senator Rubio does not speak for the majority of Cuban-Americans. A recent poll demonstrates that a large majority of Cuban-Americans actually support normalizing relations between our countries."

Paul followed up with a number of tweets to Rubio:

"Hey @marcorubio if the embargo doesn't hurt Cuba, why do you want to keep it?"

"@marcorubio what about the majority of Cuban-Americans who now support normalizing relations between our countries?"