The budget reconciliation rules that would allow Republicans to dismantle the Affordable Care Act have strict limits. The rules are primarily intended to protect legislation that affects spending or revenues. The health law includes insurance market standards and other policies that do not directly affect the budget, and Senate Republicans would, in many cases, need 60 votes to change such provisions.

Repealing the funding mechanisms but leaving in place the regulations risks a meltdown of the individual insurance market. Insurers could not deny coverage, but they would not get as many healthy new customers as they were expecting. Hospitals would again face many uninsured patients in their emergency rooms, without the extra Medicaid money they have been expecting.

Even a delay of two to three years could be damaging. Health policy experts said the uncertainty could destabilize markets, unnerving insurers that have already lost hundreds of millions of dollars on policies sold in insurance exchanges under the Affordable Care Act.

“Insurers would like clarity on the shape of the replacement plan to continue participating on exchanges if Obamacare is repealed,” Ana Gupte, an analyst at Leerink Partners who follows the insurance industry, said Friday.