If McCain is claiming that Senator Rand Paul is working for Vladamir Putin, then Senator Paul should make the claim that Senator John McCain is working for ISIS.
McCain represents a variety of special interests like the Saudis who financed the jihadis who messed up Libya and Syria and created IS.
The defense contractors who sell their wares to the Saudis and Gulf Arabs.
And the big media companies since McCain has had a leading role on committees overseeing media regulation.