Q+A-What happens next on U.S. healthcare reform?

WASHINGTON Jan 31 (Reuters) - A judge in Florida on Monday invalidated President Barack Obama's healthcare reform law after finding the requirement that Americans buy health insurance was unconstitutional, in the biggest legal challenge yet to federal authority to enact the law.

U.S. District Judge Roger Vinson ruled that the reform law's "individual mandate" went too far in requiring that Americans buy health insurance or pay a penalty and was inextricably linked to the rest of the law.

Here are some questions and answers about the political and legal challenges to the law.

WHAT HAPPENS NEXT IN THE COURTS?

The Obama administration said it will appeal the judge's ruling to the U.S. Court of Appeals for the Eleventh Circuit and is considering asking the appeals court for a stay of Judge Vinson's ruling pending that review.

Besides that case, a U.S. judge in Virginia in December declared a critical part of the healthcare law unconstitutional, in the first major setback to the reform. The case was appealed and arguments are scheduled for May.

U.S. District Judge Henry Hudson, a Republican, backed the state of Virginia's argument that Congress had exceeded its authority by requiring Americans to start buying health insurance in 2014 or face a fine.

More than half of all states now are challenging the law in the federal courts. Another federal judge in Virginia and one in Michigan upheld the individual mandate as constitutional.

Oklahoma decided to file its own lawsuit in January.

Constitutional scholars expect one of the two dozen lawsuits filed since the law was enacted to eventually make its way through to the U.S. Supreme Court, most likely the multi-state lawsuit or the Hudson ruling in Virginia.

WILL OBAMA PUT THE PLAN ON HOLD DURING COURT PROCESS?

No, not yet. Senior White House officials said after the Virginia ruling that Obama will continue implementing the healthcare reform while the court challenges play out. But the ruling in Florida could complicate those plans.

White House officials insist they are confident that the healthcare law will withstand the legal challenges.

Before the Florida ruling, the administration has had some latitude because the part of the law ruled unconstitutional, known as the individual mandate, will not come into force until 2014. Already, provisions allowing states to review increases in health insurance premiums and sending money to community health centers have moved forward.

WILL CONGRESS REPEAL THE WHOLE LAW?

It is unlikely.

Republicans control the U.S. House of Representatives but not the Senate, limiting their power to overturn the law.

House Republicans voted for repeal in January, but the vote is likely to be only symbolic. There are enough Democrats in the Senate to block repeal and they have said they do not plan to bring it up. Even if a repeal did pass both chambers, the White House says Obama would veto the bill.

HOW ELSE COULD CONGRESS ATTACK THE LAW?

Given that Republican efforts to replace the entire law are unlikely to win passage, they are expected to try to use replacement legislation to chip away at parts of it, like the requirement that every American buy health insurance.

Replacement legislation could pass the House and even win some support among Democrats in the Senate, who say the existing law is not perfect and, like any major piece of legislation, needs modifying. For example, they could adopt new curbs on malpractice lawsuits.

Obama has said he is open to "tweaking" the measure, but vows not to "refight" the months-long battle that led to the law's passage in March 2010. [ID:nN28123587]

Republicans also can try to withhold money needed to administer and enforce the law and likely will work to delay the funding. The House Judiciary Committee plans to hold a healthcare hearing each week, which would pressure lawmakers and provide a forum for dissent.

HOW ELSE CAN STATES AFFECT HEALTHCARE'S FUTURE?

Many provisions in the healthcare law were given to the states to implement. That has set them scrambling to start programs or expand existing ones at a time when revenues are scarce and some are unable to meet basic spending pressures.

Only a few provisions gave the states funds to hire additional staff or change computer systems. Adding to the confusion is the process under which the law made it out of Congress, known as reconciliation, which required lawmakers to use an early draft of the bill. By the time the healthcare law was signed, many of the legislated deadlines states had to meet had already passed.

Some states have already decided not to establish or run health insurance exchanges, open markets where individuals could buy insurance. Others are putting off expanding Medicaid, the healthcare program for the poor run by the states with federal reimbursements.

Many Republican governors have issued statewide orders to implement only those parts of the plan that are mandatory and not to participate in the optional programs. (Reporting by Donna Smith, Lisa Lambert, Jeremy Pelofsky, Susan Heavey and Patricia Zengerle; Editing by Chris Wilson)