Utter confusion could result if the Supreme Court invalidates the Affordable Care Act’s (ACA) individual mandate while upholding other parts of the law, a physician expert predicted ahead of Thursday’s expected decision.

And a split decision is, indeed, likely, said Randy Wexler MD, MPH, of Ohio State University in Columbus.

That will create chaos, he said, which is something other healthcare experts have also predicted.

“Anything less than an all-or-none ruling would create even more chaos in an already chaotic system,” Wexler wrote in an email to MedPage Today and ABC News. But, he noted, “it should also be understood that even if the law is struck down, many changes we have already seen will continue to evolve,” including pay-for-performance models and accountable care organizations.

“Reimbursement is already going down the pay-for-value pathway, and that is not going to change,” he added.

Aside from deciding whether the law’s individual mandate that everyone have insurance is constitutional and whether it can be severed from the rest of the law, the Supreme Court also will decide whether the law’s expansion of Medicaid is constitutional.

Starting in 2014, the ACA expands Medicaid to cover nearly all people under age 65 with household incomes at or below 133% of the federal poverty level.

Nancy Schlichting, CEO of Henry Ford Health System in Detroit, said she hopes the ACA is not overturned.

“America can’t afford anything less,” she said in an email to MedPage Today and ABC News. “The ACA is only a baby step in the direction we need to go to start getting the healthcare crisis, and healthcare costs, under control. Taking back even that baby step will so burden our economy with out-of-control healthcare spending and our public hospitals with the care of the uninsured that it will make us uncompetitive economically.”

Lee Green, MD, MPH, a family medicine professor at the University of Michigan in Ann Arbor, also hopes the court upholds the law.

“If the decision is split, it is very important to retain the expansion of Medicaid to reduce the number of uninsured Americans,” he said in an email to MedPage Today and ABC News, adding that he also would like to see two other provisions kept in place: one allowing young adults to stay on their parents’ insurance coverage through age 26, and the other making it illegal for insurers to deny coverage based on a person’s health status.

Susan Dorr Goold, MD, professor of internal medicine and health management and policy who is also at the University of Michigan in Ann Arbor, said she hopes the court upholds the law in its entirety.

“Why? Because, as a primary care physician, I regularly care for patients whose health suffers from lack of insurance,” she said in an email to MedPage Today and ABC News. “One patient tried to commit suicide in the past and pays in full for every therapy session I cajole him into attending. When the bills pile up he goes less often and his depression worsens.

“Another patient had a breast lump so large and irregular we barely needed a tissue sample to diagnose her cancer. She waited until she qualified for Medicare to see a doctor.”

And, she noted, “everybody knows people without insurance. They cook at your favorite restaurant, care for your children, cut your hair, deliver your newspaper, or run their own businesses. Some people lack insurance because they work part-time, care for children or elderly parents, lost a job or, ironically, because their illness impairs their ability to work.”

Dorr Goold mentioned one patient she has who is opposed to the law’s requirement that everyone have insurance. The woman asked why she should be required to have insurance when she and her family are healthy and ‘don’t run to the doctor for every little thing.'”

“People know that emergency departments, hospitals, and doctors provide care for the uninsured. In other words, they’re free riders,” she wrote. “Unless we’re willing to let her and her children die on the street – and I for one am not — we need some kind of system that requires, that mandates that people who can do so contribute to the possible future expense of their care.”

Dorr Goold also said she worries about “our most vulnerable people,” if the court decides the law’s expansion of Medicaid violates the Constitution.

The Court is expected to issue its decision, or decisions, on the law Thursday in a session that begins at 10 a.m.

Emily P. Walker is a MedPage Today Washington Correspondent.  This piece was originally published in MedPage Today.