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WASHINGTON — Alaska Sen. Lisa Murkowski won't vote for a motion to proceed on a bill that would repeal — but not replace — the Affordable Care Act, she said Tuesday.

"I'm not there," she said after stepping onto an elevator following an Energy Committee hearing. "I said in January we should not repeal without a replacement, and just an indefinite hold on this just creates more chaos and confusion."

Murkowski was headed to a vote, followed by the Senate Republicans' policy lunch, where the group was set to discuss the latest rejection of the party's legislation to undo Obamacare. Minutes later, Alaska Sen. Dan Sullivan, also headed toward the Capitol, said he would have no comment on the vote or his plans until after the policy lunch.

Murkowski's statement provided a clear blow to the bill. She joined centrist Republican Sens. Susan Collins of Maine and Shelley Moore Capito of West Virginia in opposition.

Repealing the Affordable Care Act and replacing it later was the latest — and potentially shortest-lived — effort by Republicans to tackle the Obama health care law.

When two conservative Republicans announced Monday night they would not support legislation crafted by Senate Majority Leader Mitch McConnell, R-Ky., the party officially fell below the 50 votes needed to pass the bill. (Vice President Mike Pence is available to act as a tiebreaker.)

In reaction to that bill's demise, McConnell announced he would hold a vote this week on House legislation to repeal the Affordable Care Act without any replacement mechanism. That would undo Medicaid expansion and remove subsidies that make insurance affordable for more than 80 percent of Alaskans who buy plans on the state's exchange.

The Senate voted on and passed that same legislation in December 2015, but it was vetoed by President Barack Obama. Murkowski and Sullivan both voted in favor of the bill then.

Murkowski said in a written statement Tuesday that the "individual market in states like Alaska and in rural communities across America has continued to deteriorate since we last voted to repeal the Affordable Care Act."

But she called for the Senate to instead move forward with a "bipartisan process to address the failures of the ACA and stabilize the individual markets."

"That will require members on both sides of the aisle to roll up their sleeves and take this to the open committee process where it belongs," she said.

Murkowski is a member of the Health, Education, Labor and Pensions Committee, which was not part of the efforts to move a repeal-and-replace Obamacare bill through the Senate. Instead, the bill was written by staffers for McConnell. Murkowski often lamented that fact and complained about being shut out of the process.

Murkowski was widely considered an uncertain vote for Senate Republicans seeking to overturn the Affordable Care Act with their slim, 52-person majority. The process has been driven through budget reconciliation legislation, which allows Republicans to avoid a filibuster effort and pass legislation with only 51 votes, rather than 60.

The budget reconciliation rules do, however, limit the scope of repeal to budget-and tax-related issues, complicating efforts for a "full" repeal of the law.

And a divide emerged between the more conservative and moderate members of the Republican Party, complicating the effort to get to 50 votes. Conservative Republicans wanted a full repeal of the law. Moderate senators, concerned about undoing Medicaid expansion in their states, argued to keep Obamacare provisions that require health insurers to offer coverage to all, disallowing the practice of denying coverage for people with pre-existing conditions, either explicitly or by pricing them out of the market.