Politico reports that defenders of Obamacare are vowing a “total war” campaign to keep President Trump and the GOP from repealing it:

Shell-shocked Democrats on Capitol Hill are preparing to make a fight for Obamacare their top priority in the opening days of the Trump administration, with leading advocacy groups ready to wage “total war” to defend President Barack Obama’s universal health care program and his domestic policy legacy.

“We’ve got the battle of our lifetime ahead of us,” Ron Pollack, executive director of advocacy group Families USA, said the day after Donald Trump was elected on a pledge to repeal the Affordable Care Act, which now covers 22 million people. “We’re going to have a huge number of organizations from all across the country that will participate in this effort.”…

“Sen. Schumer and Senate Democrats are interested in ways to improve the Affordable Care Act. But we will fight tooth and nail against any attempt to repeal it,” a senior Senate Democratic aide told POLITICO, referring to incoming Minority Leader Chuck Schumer.

In reality though the Democrats only have one actual means of stopping repeal: a Senate filibuster. Before looking at what else Republicans could do short of full repeal, consider that the filibuster is not as certain a thing as it might have been even a few weeks ago. Shortly before the election when Democrats felt certain they were about to take the White House and regain the Senate, outgoing Sen. Harry Reid put ending the filibuster on the table. From Talking Points Memo:

Envisioning Hillary Clinton in the White House and Democrats controlling the Senate, Reid warned that if a Senate Republican minority blocked her Supreme Court nominee, he is confident the party won’t hesitate to change the filibuster rules again (no, Reid won’t be in the Senate to make that decision, but he is the ultimate informed source on this topic).

“I really do believe that I have set the Senate so when I leave, we’re going to be able to get judges done with a majority,” Reid told Talking Points Memo. “They mess with the Supreme Court, it’ll be changed just like that in my opinion,” Reid said, snapping his fingers. “So I’ve set that up. I feel very comfortable with that.”

Over at Forbes, Avik Roy writes that Republicans could do the same thing to repeal Obamacare, “Republicans could, in theory, get rid of the filibuster, but Senate Majority Leader Mitch McConnell (R., Ky.) and others have routinely expressed opposition to that idea. (And that’s a shame.)”

Mitch McConnell may not like this idea but President Trump made a campaign promise which means he’ll be motivated to urge McConnell to change his mind. Also, Heritage Action has published a paper arguing that the law could be fully repealed using reconciliation alone, i.e. with 51 votes. Assuming that doesn’t happen, Roy notes Republicans can, at a minimum, accomplish partial repeal through reconciliation:

The best that Republicans can do is to pass a partial repeal of Obamacare using the reconciliation process, which only requires 51 votes. Republicans did this in January, when they sent to President Obama’s desk the Restoring Americans’ Healthcare Freedom Reconciliation Act of 2015.

That bill would have repealed Obamacare’s tax hikes, Medicaid expansion, and insurance exchange subsidies, affecting more than 15 million enrollees. That’s a big deal, because it affects $2 trillion of spending over the next decade.

But critically, the partial repeal bill does not get rid of Obamacare’s tens of thousands of pages of insurance regulations, the regulations that are responsible for the law’s drastic premium hikes.

Whatever approach the GOP decides to take, the ability of the law’s supporters to stop significant changes to Obamacare appears limited.