Washington (CNN) The House of Representatives began the process of dismantling the Affordable Care Act on Friday, approving a budget resolution on a mostly party line vote.

The Senate passed the measure earlier this week. It allows Republicans on Capitol Hill to use a process known as "budget reconciliation" to roll back major parts of the health care law. Top Republican leaders are also saying they plan to move to replace Obamacare along the same track, but they are still struggling to come up with the details on how it will work.

Only nine Republicans crossed the aisle to side with Democrats against the measure: Reps. Justin Amash, Charlie Dent, Brian Fitzpatrick, Walter Jones, John Katko, Raul Labrador, Tom MacArthur, Thomas Massie and Tom McClintock. No Democrats voted for the resolution.

Some Republicans, like Pennsylvania moderate Dent, said they were concerned that the GOP does not have a clear plan to replace Obamacare yet. Dent cautioned that Friday's decision could further send insurance markets into a spiral.

"If there's uncertainty and these markets are already collapsing without us doing anything, this type of action could accelerate the collapse. So we have to make sure we have clear idea how we're going to land this plane," Dent said after the vote. "Before we take this plane in the air, I want to know we're going to land it. Right now I'm not sure we can land it."

"I just couldn't vote because I think we're going a little too fast," said MacArthur of New Jersey. "That said, I understand Leadership's goals and I agree with them. We have to fix what is clearly broken with Obamcare. We have to fix that. I have for years said we have to repeal and replace."

Amash, the leader of a group of libertarian Republican members, explained afterward that he opposed the measure because of broader concerns about government spending. (Friday's vote also formally approved budget guidelines for the current fiscal year.)

"Most massive budget in U.S. history passed 227-198. It adds more than $9 TRILLION to the debt over the next decade," Amash, a Michigan Republican tweeted.

Most massive budget in U.S. history passed 227-198. It adds more than $9 TRILLION to the debt over the next decade. https://t.co/P4nqi35X0q https://t.co/XnRC8s3FaQ — Justin Amash (@justinamash) January 13, 2017

But the focus and the fight was clearly on Obamacare -- which is set to dominate much of the time in Washington in the coming months.

'Rescue mission'

"This is a signal that we are very serious about what we've campaigned on for years. It's the very beginning," said House Majority Whip Steve Scalise, who polled Republicans on their concerns before Friday's big vote. "We've said from the start, we've gotta have this first step to then go and not only repeal but replace Obamacare. I think this shows we have strong resolve to follow through on that process."

House Speaker Paul Ryan said that Republicans were now sending in a "rescue mission" to fix the massive healthcare law.

"I can't help but think back to when we were debating this law in 2010. As a member of the minority, I stood right here and pleaded with the majority not to do it. Don't take something as personal as health care and subject it to this big government experiment. Don't do something so arrogant and so contrary to our founding principles," Ryan said in a rare floor speech. "My colleagues, this experiment has failed. This law is collapsing as we speak. And we have to step in before things get even worse. This is nothing short of a rescue mission."

Minority Leader Nancy Pelosi -- who led the passage of the law in 2009 and 2010 when Democrats controlled the House -- accused Republicans of attempting to "cut and run" on people with health insurance and argued that Republicans would end up cutting Medicare benefits as well.

"The Republican replacement plan is cut and run: cut benefits, cut investments and hospitals that care for our people, cut jobs. It's with no positive upside to it," Pelosi said. 'We are not going to identify ourselves with cut and run, cutting benefits, cutting of those covered and cutting the savings that we have there."

By using the budget process, Republicans are taking advantage of the same process which Democrats used seven years ago to pass the law -- using a special budgeting rule that allows them to skirt a filibuster in the Senate.

But that strategy only works for fiscal measures in the healthcare law -- like tax credits -- and leaves untouched some of the more popular slices of the law, like allowing children to stay on their parents' plans until they are 26.

The vote will clear the decks for Republicans to begin working on a repeal of the law -- but the larger debate has engulfed the Capitol over how and when Republicans would replace the law.

The debate over replacement has exposed some rifts within the Republican Party, which now controls the White House and both chambers of Congress -- the same position Democrats were in seven years ago.

Some conservative Republicans, including members of the small but influential House Freedom Caucus, balked at the measure -- citing concerns about the timeline to replace Obamacare, and the lack of spending cuts in the underlying budget being voted one.

At the same time, more moderate members of the party are concerned about the party moving forward with repeal without more detailed replace plans. Millions of Americans could lose health insurance if Obamacare was rolled back before a replacement was in place.

The budget concerns have prompted Kentucky Sen. Rand Paul to vote against his party and the bill in the Senate, though Republicans still had the votes needed to pass it. Leadership insists that the resolution is only a shell for the budget, and not the final numbers.

But any replacement measure un-related to the budget will have to clear 60 votes in the Senate -- a prospect that requires Democratic support, as Republicans only have a 52-seat majority. Republicans also have several competing plans to replace Obamacare, and No. 2 Senate Republican John Cornyn has indicated that the party may opt to move smaller pieces of legislation as opposed to one overarching replacement.

Ryan told CNN's Jake Tapper at a town hall that the goal is to move everything at once.

"We want to do this at the same time, and in some cases in the same bill," Ryan said. "So we want to advance repealing this law with its replacement at the same time."