The U.S. Senate will hold votes Wednesday on amendments to a new gun control bill.
The amendments include a provision that would expand background checks on gun buyers, which is considered a key component of the overall bill. The amendment is a compromise between Democrat Joe Manchin and Republican Pat Toomey, two pro-gun lawmakers.
But as of late Tuesday, Senate leaders appeared to be a few votes short of the 60 needed for approval. A handful of senators remain undecided, including Democrats from conservative leaning states.
Fomer U.S. Representative Gabby Giffords, who was seriously wounded in mass shooting in Tuscon, Arizona in 2011, is visiting Capitol Hill to show her support for the compromise Manchin-Toomeny amendment.
Other amendments up for a vote Wednesday incudes a ban on sales of military-style assault weapons, and a limit on the size of ammunition clips, both of which are expected to fail.
The overall Senate bill was drafted in response to last December's massacre of 26 children and teachers at an elementary school in Newtown, Connecticut, as well as other mass shootings across the U.S. in recent years. The legislation would also increase funding for school safety and set new penalties for gun trafficking.
The National Rifle Association, the powerful gun owners group, opposes the new gun-control measures on the grounds they violate the constitutional right to own weapons. Any gun control legislation must also pass the Republican-controlled House of Representatives.