PORTLAND, Maine — Sen. Susan Collins appeared on CBS’s “Face the Nation” Sunday morning from the WGME studios, explaining why she is not voting for her party’s presidential nominee.

Before going on “Face the Nation,” Collins sat down with CBS 13 and explained why she’s not voting for Donald Trump and who she could cast her vote for in November.

“Donald Trump simply lacks the temperament, the judgment, the knowledge and the self-control to be our president,” Collins said. “It wasn’t easy for me to disavow the nominee of my party.”

Earlier this month Collins made her feelings known in an op-ed in the Washington Post. Collins said her first choice for president was Jeb Bush, but once Trump clinched the nomination, she thought he might change.

“It’s been a very unpredictable year,” Collins said. “Frankly, every prediction I’ve made [is] wrong so far.”

Collins said she decided to not back Trump after what she calls continued mocking and criticism, including his actions towards the parents of a fallen Muslim-American soldier.

“That was just a bridge too far for me,” Collins said. “He should have been honoring their sacrifice and empathizing with their pain.”

But Collins said she hasn’t disagreed with everything the Republican nominee has said.

“When mills have closed down throughout the state, Donald Trump is right that neither party has reached out to those displaced workers and those families who are really hurting,” Collins said.

Collins said she can’t support Hillary Clinton either. She said she is considering the Libertarian ticket, but that’s not a sure thing either.

“I may write in a candidate who I believe would be best qualified to lead our country,” Collins said.

Some say the fourth-term senator is shying away from her party with these comments. But Collins said she wants them to know she will always be a lifelong Republican.

“I’m going to continue to work hard for Republican candidates across the country,” Collins said. “But I simply can’t support Donald Trump for president.”