Hillary Clinton’s presidential bid is getting a boost from William Cohen, a former Republican Maine senator who served as Bill Clinton’s defense secretary.

Cohen said on MSNBC that he would be uncomfortable with Donald Trump making decisions on “existential” issues. He said Trump lacks the necessary knowledge of the military, world history and global issues.

He said Clinton, a former secretary of state, has experience in the White House situation room and that he would feel more comfortable with Clinton having access to nuclear codes.

Asked if he would vote for her, Cohen said: “In all likelihood, I would say yes.”

He said he would have supported former Florida Gov. Jeb Bush or Ohio Gov. John Kasich if one of them had been on the ballot.