The U.S. Supreme Court is likely to hand down its ruling on the federal health care law.

Predictions from experts are all over the place -- some believe the court will throw out the whole law, some are saying it will uphold all of it.

Most believe it will overturn portions, particularly the mandate that all Americans must buy health coverage, something conservatives have attacked relentlessly as a constitutional violation.

Perhaps the biggest impact in Indianapolis will be on Wellpoint.

But the giant insurer isn't talking yet and said it would comment after the ruling.

Some legal experts said the individual mandate is too big a constitutional stretch of the federal government's ability to regulate behavior under the interstate commerce clause.

But Indiana University law professor David Orentlicher, a constitutional expert, said he believes the court will uphold the entire law.

He said the mandate can be compared to the existing requirement that all Americans enroll in Medicare.

"Medicare is a critical example, because think about Medicare,” said Orentlicher. “What is Medicare? Medicare is a mandate for us now when we're younger than 65 to pay for our health care insurance, so when we reach 65, we'll have health care then. That's a mandate. We do it through a payroll tax."

If the mandate is overturned, Orentlicher said that will be bad news for other popular but expensive features, such as the one requiring coverage of pre-existing conditions.

He said allowing some people to opt out of coverage will make that feature too expensive for insurance companies.

"And that's not fair to allow people to game the system. It would be like saying to people, 'You can wait until your house is on fire to buy your homeowners insurance.'"

The head of the Indiana Chamber of Commerce said business doesn't know what to prepare for.

He believes if the mandate is thrown out but other requirements remain that many companies may wind up dropping insurance coverage completely.

"The whole incentive system is for business to drop coverage and pay the penalty, because in most cases the penalty is far less than current coverage,” said Kevin Brinegar. “And it's not only conspiracy theorists who think that it was done that way as an intermediate step toward universal health care."

And some people are envisioning a possible nightmare scenario: the court throws out the mandate and the Republican House refuses to replace it with anything, but the Democratic Senate refuses to remove the other provisions insurance companies then wouldn't be able to afford.