Snowe said in a statement Tuesday that as conditions in Iraq continue to worsen, "there must be no question among the (Bush) administration, the Congress and the Iraqi unity government that staying the course is neither an option nor a plan."
The second-term senator, who is seeking re-election Nov. 7, said she agrees with Senate Armed Services Committee Chairman John Warner, who has called for a reassessment of the U.S. strategy in Iraq.
On Sunday, James Baker III, a former secretary of state with a longstanding reputation of caution and service to Republican presidents, also joined the list of prominent Republicans lobbying for change in President Bush's Iraq policy.
In her statement, Snowe noted that last December the Senate passed an amendment by Warner calling 2006 a year of transition for the United States in Iraq.
"Yet, with fewer than three months remaining, I am deeply disturbed that 2006 has become a period marked by increased sectarian violence, as opposed to an increased ability of the Iraq government to secure its own nation," Snowe said.
"The message must be loud and clear: The Iraqi government does not have unlimited time to seize control of their country and their security by firmly confronting the sectarian violence and disarming the militias before their country reaches a point of no return," the statement said.
Snowe said Congress and the administration should be open to alternative plans for the U.S. role in Iraq. One option, she said, could be convening an international summit of international stakeholders to set a path forward in Iraq.
Maine's other senator, Republican Susan Collins, has been quoted as saying there was a "growing sense of unease" about the war among other Republicans. Collins told The New York Times that Republicans' concerns could deepen because of Warner's call for a reassessment.
"When Chairman Warner, who has been a steadfast ally of this administration, calls for a new strategy, that is clearly significant," Collins, who chairs the Senate Homeland Security Committee, told the Times.
In Maine, Snowe's re-election challenger said her statement reflects an "election year conversion."
"She is not leading in the party. She is a follower," said Democrat Jean Hay Bright, who has criticized Snowe throughout the campaign for supporting the Iraq war. "Unfortunately, it took her this long to figure out this is the wrong course for America."