Sen. Susan Collins, R-Maine, told NBC News that she intends to vote yes on bipartisan legislation to expand background checks on gun purchases.
Collins said she has now reviewed the actual text of the Manchin-Toomey bill and thinks it is a "reasonable" approach.
"I do intend to support it," Collins told NBC.
The Manchin-Toomey compromise includes expanding background checks to include purchases at gun shows and online but will not cover individual sales.
Collins said she would not have supported a plan that included such individual sales, citing an example of a father who gives his daughter a gun for protection when she "moves to the big city."
Collins told NBC that she was "being hit hard" and "I am being besieged by all sides" referring to ads run against her by both the conservative "National Association of Gun Rights" and the president's group, Organizing for America.
A recent CNN poll found that 86 percent of those questioned said they support some form of background checks that are not currently required by law for gun sales.
Collins' public support is a critical step for the bill's sponsors who are relying on some Republican support to pass expanded background checks.
Another Republican, Sen. Mark Kirk from Illinois, worked with Manchin and Toomey privately during negotiations and is expected to vote yes on the background checks bill but has not said so publicly.