Maine’s Republican Sen. Susan Collins jointly wrote a letter to Secretary of State Rex Tillerson expressing support for maintaining U.S. participation in the Paris climate agreement.

“Climate change is a significant environmental challenge that requires global solutions to reduce greenhouse gas pollution and to address the effects already seen worldwide. For international climate efforts to advance, it is essential that the United States keep a seat at the table,” the letter says. Sen. Ben Cardin of Maryland, the ranking Democrat on the Senate Foreign Relations Committee, signed with her.

The letter also cites the economic costs of climate impacts and national security implications of climate change. With nearly every country in the world a signer and 65 percent an official party to the agreement, Collins argues that “even if the U.S. opts out, the rest of the world will proceed with mitigation strategies without us and decisions they make will affect us, regardless of our absence.”

A decision from the White House on whether the U.S. will stay in Paris is imminent.