WASHINGTON — A crack just formed in Trump’s impeachment wall.

Alaska Sen. Lisa Murkowski, a moderate Republican who President Trump wants to help stop his impeachment cold when it finally reaches the Senate, went wobbly on him over the Christmas break.

Murkowski declared herself “disturbed” by GOP Senate Majority Leader Mitch McConnell’s pledge of “total coordination” with the White House, in an interview Murkowski gave to NBC’s local Alaskan affiliate KTUU on Tuesday evening, Christmas Eve.

“We have to take that step back from being hand-in-glove with the defense,” Murkowski said. “I heard what leader McConnell had said. I happen to think that that has further confused the process.”

Her remarks won’t sit well in the White House, which wants the Republican-dominated Senate’s unanimous support both for clearing Trump and in keeping potentially explosive administration witnesses from speaking out during the trial.

While Trump’s still widely expected to sail through the Senate without much trouble, a small minority of moderate Republican Senators could theoretically throw their weight around and force changes in the trial process if they stood together with Democrats, who’d would need four Republican defectors to achieve a majority vote.

Senate Democrats are demanding that more White House insiders testify about what Trump did, but they won’t get any without at least a little Republican support.

The Senate’s top Democrat, Chuck Schumer, proposed bringing in four administration witnesses to testify in the Senate, including Trump’s former National Security Advisor John Bolton and Trump’s White House Chief of Staff Mick Mulvaney.

Schumer also wants documents, including a lengthy list of communications between top Trump officials about how and why vital military assistance to Ukraine was withheld.

The question now is just where exactly Murkowski stands about all that — and whether any of her GOP colleagues agree with her.

Despite taking a shot at McConnell’s pledge for total unity with Trump’s White House on impeachment, she didn’t exactly go full-on, Anti-Trump resistance.

She also criticized House Democrats for failing to bring in even more witnesses from Trump’s administration, like Bolton or Mulvaney. (Democrats say the courts might have taken months to decide whether they should appear.)

“If the House truly believed that they had information that was going to be important, they subpoena them,” Murkowski said. “And if they ignore the subpoena, as they did, at the direction of the White House, then that next step is to go to the courts.”

House Democrats impeached Trump, after hearing from over a dozen witnesses, on two counts earlier this month: One for abusing his office by pressuring Ukraine to announce investigations of Democrats, and a second for obstructing Congress’s investigation into what happened.

Murkowksi insisted she hasn’t yet decided how she’ll vote in the end.

“For me to prejudge and say, ‘There’s nothing there,’ or, on the other hand, ‘He should be impeached yesterday,’ that’s wrong,” she said. “In my view, that’s wrong.”

Either way, one “disturbed” Republican Senator is still a long way from the two-thirds Senate majority needed for actually kicking Trump out of office. Right now, that still looks like an impossible benchmark in a 100-member body with 53 Republicans.

Cover: Sen. Lisa Murkowski, R-Alaska, walks to the Senate subway after a vote in the Senate on Tuesday, June 18, 2019. (Photo By Bill Clark/CQ Roll Call)