The two non-voting senators were Republicans. One was Rand Paul who co-sponsored the bill, apparently there's some tradition of not voting for your own bill (wh

The two non-voting senators were Republicans. One was Rand Paul who co-sponsored the bill, apparently there's some tradition of not voting for your own bill (when there are votes to spare). The other one, Isakson, is recovering from surgery and not in D.C. to vote.