House Speaker Paul Ryan said President Barack Obama's health care law is entering its final stage of life.
"You have to remember this law is getting much worse. It is what actuaries say, 'Entering a death spiral.' High, high premiums increase, high deductibles, no choices. We have to fix this problem," the House speaker told CNBC.
President-elect Donald Trump campaigned on a pledge to "repeal and replace" the law, known as Obamacare. He seized on rising premiums under the plan, which has broadly expanded health coverage in the United States.
Ryan vows to use the early days of Trump's presidency to "fix" the insurance system.
The Wisconsin Republican said he wanted to stress that a "reasonable" transition period would follow a repeal, "so we're not pulling the rug out from under people midstream."
About 20 million people are covered under Obamacare, the Department of Health and Human Services said earlier this year.
Ryan's agenda includes a possible replacement plan for the health care law. It would rely on individual tax credits, expand health savings accounts and allow insurance sales across state lines.
In a wide-ranging interview, Ryan tried to curb concerns about Trump's business conflicts.
Trump can separate from his empire "however he wants to," Ryan said.
"I have every bit of confidence he's going to get himself right with moving himself from the business guy that he is to the president he's going to be," Ryan told CNBC.
"This is not what I'm concerned about in Congress. ... I'm focused on getting this agenda passed so that we can turn around and tackle this country's big problems before they tackle us. That is what I'm focused on and not the legal details of how he divorces himself from his business, which I know he will," he added.
Meanwhile, Obama has encouraged Americans to sign up for Obamacare health insurance plans despite Republicans' stated intentions to repeal, or at least improve, the law during Trump's administration.
According to The Hill, Obama spoke on a Facebook Live video and urged people to sign up by Dec. 15, which would guarantee them coverage starting Jan. 1.
"Don't let Republicans in Congress take us back to the days when you could be denied insurance for having a pre-existing condition," Obama said.
He added that the Affordable Care Act is still federal law despite some politicians' arguments that "might make it sound like your insurance is somehow at risk."
Republican lawmakers are vowing to make changes to the law, if not get rid of it altogether, now that the GOP controls the White House and both chambers of Congress.
And, according to a recent report, they are working with insurance companies to make the transition between the existing law and the one that may replace it smooth at the consumer level.
Republican leaders admitted that replacing the law could take years because of its complexity.