The proposal, which Schumer (D-N.Y.) said had the backing of gun-rights allies in the Senate, would let gun owners with concealed-carry permits in one state transfer those rights to any other state, effectively overriding strict restrictions in states such as New York.
If ratified, the amendment could mean anyone with a concealed-carry permit from another state could carry their concealed weapons here, possibly turning the state into an Old West-style battleground like the "O.K. Corral," Schumer said.
"We don't want the federal government forcing it on us, our police, our citizenry," he said.
Schumer, standing in his Manhattan office at a morning media conference with local law enforcement officials -- including Nassau County Police Benevolent Association vice president Pete Paterson -- also warned that the amendment would endanger residents and police.
A so-called "reciprocity" measure, put forth in the Senate in 2009 by Sen. John Thune (R-S.D.), came within two votes of advancing to final passage. Schumer said he believed Thune would be the one to offer the measure this time around.
A spokeswoman for Thune declined to comment Sunday.
The National Rifle Association did not return a request for comment. The group's website reports that it opposes the current gun-control bill and instead advocates legislation "addressing mental health inadequacies; prosecuting violent criminals; and keeping our kids safe in schools."
Paterson said after the news conference that passage of the reciprocity measure would make it harder to do some police investigations because of the difficulty of verifying out-of-state concealed-carry permits. "There's really no way to check if that license is valid or not," he said. National reciprocity could also lead to forged licenses, Paterson said.
The Senate voted 68-31 last week to proceed with debate on gun-safety proposals, including expanded background checks and strengthened laws against illegal gun trafficking. Schumer said that the Senate could vote Tuesday on background checks, a critical piece of the legislation, but offered no prediction on the outcome.
"It's going to be nip and tuck," he said. "It's right on the edge."