Liberal justices on the U.S. Supreme Court signaled a willingness Wednesday to throw out key parts of President Barack Obama's health care law if their conservative colleagues strike down its mandate that Americans get medical insurance or pay a fine.

Several on the court appeared to accept the administration's argument that at least two key insurance changes are so intertwined with the individual mandate that they couldn't withstand its removal -- requiring insurers to cover people regardless of existing medical problems and limiting how much can be charged in premiums based on a person's age or health.

But It wasn't clear from Wednesday's oral arguments if other, less crucial pieces of the 2010 Patient Protection and Affordable Care Act might stand even if the insurance-purchase mandate is ruled unconstiutional.  

The high court's ideological split was evident at the start of a third and final day of agruments over the law's fate. Tense, back-and-forth questioning contrasted with Tuesday's court session, at which conservative justices homed in on a White House lawyer to explain why the individual mandate doesn't amount to government intrustion in markets and people's lives. 

The mandate, which would subject non-participants to a fine,  is the most disputed piece of the 2010 law.

In their questions Wednesday, Justices Sonia Sotomayor, Elena Kagan, Ruth Bader Ginsburg and Stephen Breyer took issue with Paul Clement, the lawyer representing 26 states seeking to have the law struck down in its entirety.

What's wrong with leaving this in the hands of those who should be fixing this? asked Sotomayor, an Obama nominee to the court, referring to Congress.

Chief Justice John Roberts also spoke about parts of the law that have nothing to do with any of the things we are talking about.

Clement had begun the session by arguing that the entire law should be scrapped if a majority of justices determine the individual mandate is illegal under the Commerce Clause of the Constitution. The clause gives Congress the power to regulate interstate commerce by, among other things, levying taxes that benefit the populace.  

Although the Supreme Court -- including some of the currently serving conservative justices -- has previously upheld federal statutes regulating all types of businesses, Clement insisted that Congress had never passed a law forcing Americans to buy a product or service until it did so through the health care law's insurance mandate.

The high court's official Scotus blog reported that most of the nine justices Wednesday appeared skeptical of the idea that the entire law should die if the mandate is voided. The report added that the four liberal justices' questions seemed to indicate concern that the mandate will be found unconstitutional.

Almost all of the justices questioned Clement's reasoning, according to Scotus blog, which added that many appeared unconvinced by the lawyer's claim that the health care law would be a hollow shell if the mandate and its related provisions were overturned.

The Obama administration has argued that if the mandate is stricken, only the provisions on pre-existing conditions and premiums would have to fall.

Deputy Solicitor General Edwin Kneedler, who was arguing the administration's position Wednesday, was also faced with seemingly incredulous questions from some of the court's conservative justices. In particular, Scotus blog reported, they pressed Kneedler as to how the court should determine which provisions must go if the mandate is struck down.

The court has appointed an outside private lawyer, H. Barton Farr III, to argue that all of the health care law's other provisions can survive without the insurance mandate, as was determined in a ruling last August by the 11th U.S. Circuit Court of Appeals in Atlanta.

During the court's afternoon session the justices will review whether Congress violated the Constitution by coercing states to dramatically expand the Medicaid health care program for the poor under the Affordable Care Act. That expansion would make as many as 30 million more Americans eligible for Medicaid coverage.