Sen. John McCain accused Sen. Rand Paul Wednesday of serving the interests of Russian President Vladimir Putin after Sen. Paul opposed a Senate consent request for Montenegro to join NATO. 
Paul, an avowed libertarian, has often pushed for non-interventionist foreign policy goals and has voiced his opposition to the U.S.' leading position in NATO, of which Washington has been by far the biggest financial supporter. But McCain told lawmakers that acceding to Paul's objection to Balkan nation Montenegro joining the international military alliance would be to serve Moscow's interests. NATO has undergone a massive military escalation in the past year to counter what its members describe as Russian aggression after the 2014 annexation of Crimea from Ukraine. 
"You are achieving the objectives of Vladimir Putin...trying to dismember this small country which has already been the subject of an attempted coup,” McCain said, without initially mentioning Paul by name, according to CBS News.
The charge apparently prompted Paul to leave the room, further provoking McCain, who went on to "note the senator from Kentucky leaving the floor without justification or any rationale." McCain blasted Paul for not getting on board with what he said were about 98 of his colleagues who reportedly supported Montenegro's NATO membership bid. He then accused Paul of directly working for Putin.
https://www.newsweek.com/cold-war-mccain-paul-russia-nato-568816