PHOENIX -- Arizona Sen. John McCain said Wednesday that he will vote for legislation that expands background checks on gun purchases.
McCain made the announcement on the Senate floor as it appeared the chances of the bill passing were diminishing.
In backing the bipartisan agreement that was reached between Sens. Joe Manchin, D-West Va., and Pat Toomey, R-Penn., McCain became one of only a handful of Republicans to support the measure.
A vote on the Manchin-Toomey agreement is set for later today. But it appears the deal will fall short of the 60 votes needed, according to numerous published reports.
During his floor speech, McCain acknowledged that it may not pass and praised Manchin and Toomey for having what he called "political courage."
Arizona's senior senator also said the proposal was, "not overly burdensome or unconstitutional."
Opponents of the measure like the National Rifle Association have been working hard to kill the measure.
For gun control advocates, it represented the best chance for passing gun-control legislation this year.