(Susan Collins and Donald TrumpKevin Lamarque/Reuters)

Sen. Susan Collins of Maine announced Monday that she will vote "no" on the latest Republican healthcare bill, all but surely ending the latest effort to repeal and replace Obamacare.

Collins joins Sens. John McCain and Rand Paul in opposition, and since two GOP members could oppose the bill for it to pass, the bill is likely dead. The Maine senator also opposed the previous iterations of the Republican healthcare bills, helping to end that push in July.

"Sweeping reforms to our health care system and to Medicaid can’t be done well in a compressed time frame, especially when the actual bill is a moving target," said a statement from Collins. "Today, we find out that there is now a fourth version of the Graham-Cassidy proposal, which is as deeply flawed as the previous iterations."

Collins pointed to three primary issues with the bill that caused her to oppose it:

1. Cuts to Medicaid, estimated at roughly $1 trillion from 2020 to 2036, by shifting to a block grant system: "This would have a devastating impact to a program that has been on the books for 50 years and provides health care to our most vulnerable citizens, including disabled children and low-income seniors," Collins said.

2. Weakened protections for people with pre-existing conditions: "Some states could allow higher premiums for individuals with pre-existing conditions, potentially making their insurance unaffordable."

3. Health insurance coverage losses: "Third, physicians, patient advocates, insurers, and hospitals agree that both versions of this legislation would lead to higher premiums and reduced coverage for tens of millions of Americans," said the statement.

Collins also said that despite the recent change by the authors of the Graham-Cassidy bill to include more money for her state in their formula for the new block grants, the overall cut was still too great for her to stomach. Additionally, Collins took issue with the seat-of-the-pants changes to the formula that lead to her state gaining more money.

"But even more important, if Senators can adjust a funding formula over a weekend to help a single state, they could just as easily adjust that formula in the future to hurt that state," Collins wrote. "This is simply not the way that we should be approaching an important and complex issue that must be handled thoughtfully and fairly for all Americans."

This is likely the last time in quite a while that Republicans will be able to advance any sort of large Obamacare repeal measure, since the deadline to use budget reconciliation — which allows a simple majority vote and no filibuster — runs out September 30.