WASHINGTON ― In his final Senate press conference of 2016, Majority Leader Mitch McConnell (R-Ky.) renewed his pledge to start repealing the Affordable Care Act on Jan. 3 even with no replacement in sight, declaring that “surely” the GOP revision will wind up covering Americans better than Obamacare.

He declined to say when or how Republicans will pass their superior “replacement” plan.

“Eighty-five percent of Americans have coverage, and there’s still roughly 25 million who don’t,” McConnell told reporters Monday, understating the portion of the nation with health insurance by about six percentage points. And although some 28 million people still don’t have insurance, according to the Centers for Disease Control, that’s roughly 20 million fewer than before the landmark health law took effect.

McConnell, however, dismissed this progress. “If coverage was the issue, Obamacare was an abysmal failure,” he said. “Surely, we can do better for the American people.”

Exactly how Republicans intend to do better remains to be seen. It took House Republican leaders over six years to agree on a set of principles for replacing Obamacare, and they still have yet to flesh out those principles with numbers that would give a clear sense of what their scheme would mean in practice. Senate leaders, meanwhile, haven’t even gotten as far as a set of principles.

That uncertainty doesn’t seem to be giving McConnell and his allies pause, however. On Monday, McConnell made it clear he was committed to moving quickly on a repeal bill ― just as House Speaker Paul Ryan (R-Wis.) and officials from the incoming Trump administration have.

The process would start on Jan. 3, when the new Congress is expected to pass a bill rescinding Obamacare’s revenue and spending portions using the budget reconciliation process. The advantage of a reconciliation bill is that, by rule, Democrats can’t filibuster it ― which would make it possible for Republicans to pass the bill with their 52-seat majority.

The disadvantage of using reconciliation is that such a bill can only include measures directly affecting the federal budget. Repealing other aspects of Obamacare, including rules on how insurers operate, would require a separate step, as would passing an actual replacement. That would have to be done via regular legislation, which would require 60 votes.

“We will move right after the first of the year on an Obamacare replacement resolution, and then we’ll work expeditiously to come up with a better proposal than current law, because current law is simply unacceptable and not sustainable,” McConnell said.

Some Republicans have suggested taking as long as three years to craft the replacement. McConnell would not even commit to that strategy, and he repeatedly declined to discuss what a Republican-crafted health insurance system might look like.

“We’re going to move forward first with the Obamacare replacement resolution. What comes next is what comes next,” McConnell said. “In other words, legislatively, then we will determine what the replacement is going to be.”

Numerous experts, echoing warnings from health care industry groups, have said that repeal of the law could immediately throw Obamacare markets into turmoil, even if elements of the coverage expansion were kept in place for some period of time.

The concern is about insurers who have been weathering losses in the hopes of realizing future profits in the state marketplaces that Obamacare created. If those markets aren’t going to exist in a few years, neither will the profits, and insurers would have every reason to pull out now. They would be even more likely to stop offering coverage, experts have said, if the repeal bill strips out the law’s individual mandate ― because without that mandate, healthy people would be less likely to sign up for coverage, causing insurers to lose even more money.

Just last week, a report from the nonpartisan Urban Institute warned that the kind of repeal-and-delay strategy McConnell has in mind could, in a worst-case scenario, cause millions of people to lose coverage next year.

McConnell downplayed such concerns, insisting that stakeholders want the GOP to proceed.

“They want changes too,” McConnell said. “And we’re going to work with them to come up with a better situation than this monstrosity that was left behind by the Obama administration.”