WASHINGTON — President Donald Trump on Wednesday lashed out at a Republican senator who opposed moving forward with long-promised legislation to repeal and replace “Obamacare.”

“Senator @lisamurkowski of the Great State of Alaska really let the Republicans, and our country, down yesterday. Too bad!” Trump tweeted.

Murkowski, who was re-elected to a new six-year term last year, defended her vote. She repeatedly has expressed concerns about deep Medicaid cuts in the GOP bill and has called for a bipartisan process to address shortcomings of the current health care law and stabilize individual markets.

“You know I am comfortable with the decision that I made yesterday in working to advance Alaska’s interests and working today to do the same,” she said Wednesday.

“I don’t’ really follow Twitter that much,” she added.

Murkowski was one of two Republicans — Maine’s Susan Collins was the other — who on Tuesday voted against allowing debate of GOP legislation to repeal much of the Affordable Care Act. The final tally was 51-50, with Vice President Mike Pence breaking the tie.

Trump has been pushing lawmakers to deliver on their promises to repeal and replace. Whether Republicans can find consensus remains unclear.

Collins also commented on Trump’s attack on Murkowski.

“I thought it was extremely unfortunate. Lisa is an extraordinarily good senator. She represents her state very well and she’s very strong and does what she thinks is right and I was disappointed to see that.”

Murkowski, 60, is in her fourth term representing the nation’s largest state and chairs the powerful Senate Energy Committee. Murkowski, whose father served as senator and governor, survived a near-death political experience in 2010 when she lost her party’s primary but retained her seat as a write-in candidate.