President Trump says he'll endorse anyone with 'a pulse' against GOP Sen. Lisa Murkowski

President Donald Trump vowed Thursday to campaign for anyone with "a pulse" against Republican Sen. Lisa Murkowski, after the lawmaker from Alaska told the media she could not commit to voting for Trump in November.

What are the details?

"Few people know where they'll be in two years from now, but I do," President Trump tweeted. "In the Great State of Alaska (which I love) campaigning against Senator Lisa Murkowski. She voted against HealthCare, Justice Kavanaugh, and much else..."

He added, "Unrelated, I gave Alaska ANWR, major highways, and more. Get any candidate ready, good or bad, I don't care, I'm endorsing. If you have a pulse, I'm with you!"

The day before, the president lashed out at his former secretary of defense, Jim Mattis, after the retired general criticized President Trump over his leadership. Mattis accused Trump in a statement to The Atlantic of making "a mockery of our Constitution." The president fired back over Twitter that Mattis was "the world's most overrated general," and that he was "glad [Mattis] is gone."

In response to Mattis' comments, Murkowski told congressional reporters on Thursday, "I was really thankful. I thought General Mattis' words were true and honest and necessary and overdue and I have been struggling for the right words."

She continued, "I was encouraged a couple of nights ago when I was able to read what President Bush had written and I found that to be empowering for me as one leader, but then when I saw General Mattis' comments yesterday, I felt like perhaps we're getting to the point where we can be more honest with the concerns that we might hold internally, and have the courage of our own convictions to speak up. And so, I'm working as one individual to form the right words, knowing that these words really matter."

The Hill reported that when Murkwoski was asked whether she would vote for President Trump in 2020, she replied, "I am struggling with it. I have struggled with it for a long time." She acknowledged that Trump is "our duly elected president" and added that she would "continue to work with him" and "with his administration."