A new report from the Government Accountability Office suggests the federal health care law could hold together even if the Supreme Court strikes down the individual mandate.

The report, requested by Sen. Ben Nelson, D-Neb., makes clear that the mandate is critical to the health care policy-without it, Americans with health insurance would be on the hook for an estimated $57 billion to cover increasing numbers of uninsured people.

But the report lists alternatives that could potentially hold the health care law intact if the Supreme court rules against the individual mandate.

It suggests modifying insurance open enrollment periods and imposing late fees, expanding employer input in facilitating health insurance enrollment and auto-enrollment, conducting a public education and outreach campaign and providing broad access to personalized health insurance enrollment assistance. The authors of the report wouldn't endorse any of the options saying only that they were possibilities that were discussed in drafting the report.

"Washington needs to explore the GAO report's alternatives and others to see if there is a successful way to improve health reform," Nelson said in a statement.

The Congressional Budget Office has reported that without an individual mandate, the current health care law would lead to 16 million more uninsured people and would cost those who do have insurance between 15 and 20 percent more for their premiums.

And without an individual mandate or an alternative, health care experts say there could not be a ban on denying coverage due to preexisting conditions. In that case, sick patients could, in essence, buy health insurance on their way to the hospital, a practice likened to someone buying homeowner's insurance after a fire has already started in the house.

But the ban on pre-existing conditions has been one popular aspect of an otherwise increasingly unpopular law.