(CNN) - Sen. Susan Collins, R-Maine, became the second Republican senator not involved in negotiating a bipartisan background check measure to say she will support it, according to a statement Sunday.
She described the bill as a responsible compromise between two senators - Sens. Pat Toomey, R-Pennsylvania, and Joe Manchin, D-West Virginia - who have strong ratings from the National Rifle Association. Sen. Mark Kirk, R-Illinois, has indicated his support for the deal.
Collins said previous language requiring background checks on sales between family members was “onerous and completely unnecessary,” citing the omission of that requirement in the Toomey-Manchin deal as one facet leading to her support.
“The Manchin-Toomey compromise takes a much more common sense approach by requiring background checks only for commercial transactions and exempts family gifts and transfers,” she wrote.
Collins’ support for the background checks deal was first reported by NBC.
Collins and 15 other Republicans voted Thursday to begin debating the gun issue, helping Democrats reach the 60 votes necessary under the threat of a filibuster. Democratic Sens. Mark Begich of Alaska and Mark Pryor of Arkansas, both from conservative states and up for re-election in 2014, voted against it.
Collins is also up for re-election next year and hails from a state where gun ownership is strong.
"I grew up in Northern Maine where responsible gun ownership is part of the heritage of virtually every family,” she wrote. “I strongly support our Second Amendment rights, and two recent Supreme Court decisions in District of Columbia v. Heller and McDonald v. Chicago make clear that those constitutional rights pertain to the individual.”
The compromise reached by Toomey and Manchin - as well as Sens. Chuck Schumer, D-New York, and Mark Kirk, R-Illinois – would extend the current federal background checks to sales made at gun shows and between states over the Internet. It would also require all states to recognize concealed weapons permits issued by other states.
It has the backing of President Barack Obama but was rejected by the National Rifle Association. Procedurally, it will be offered as an amendment to the bill proposed by Senate Majority Leader Harry Reid that senators agreed to begin debating.
In her statement Sunday, Collins noted the final bill has yet to be determined.
"Obviously, this debate has just begun, and this important amendment is just one of many that will be considered,” she wrote. “The Manchin-Toomey amendment is a proposal I can and will support, but it is impossible to predict at this point the final composition of the overall legislation."
Collins found herself in the spotlight on the issue after her office initially offered the relatives of Newtown, Connecticut, shooting victims a meeting with her staff rather than the senator. Collins did end up meeting with the families on Wednesday and told both NBC and Politico that she was deeply moved by the conversation.