The background, as best as I can tell, is basically that there is a bill concerning a peace treaty for Montenegro which is a part of NATO, and one Senate member is able to block the measure with an objection.
Adding perspective to these comments from a year-and-a-half-ago is that a couple week ago, Rand Paul went to Moscow and met with several Russian leaders – and he now wants Trump to take some of these Russians off the sanctions list. As he told “Fox News”, he’s going to ask Trump, “Why don’t we take people off the list who are in the legislature?”
Here then is the speech by John McCain on the Senate floor, aware that Rand Paul appears poised to object to the bill and thereby block it. Watch it to the VERY end –