WASHINGTON — Former congressman Gabrielle Giffords is returning to Capitol Hill today to help kick-start a long-shot campaign to expand criminal background checks to all commercial firearms sales.

Similar legislation that sought to expand background checks failed to get a hearing in the House last session. With the GOP expanding its majority and winning control of the Senate, prospects for the bill may be even more unlikely this session.

Still, Democratic Rep. Mike Thompson of California predicts the legislation would pass if GOP leadership would let it come to the House floor.

The National Rifle Association opposes expanding background checks, saying many people sent to prison because of gun crimes get their guns through theft or the black market, and no amount of background checks can stop those criminals.