Republican plan for PPACA subsidies won't prevent 'massive disruption,' report concludes

The legislation also would repeal the PPACA individual mandate. That would exacerbate the disruption, as mandate repeal "could result in adverse selection that would raise premiums and threaten the viability of the market." 

While Johnson's plan has the support of Senator Majority Leader Mitch McConnell, R-Ky., it isn't faring well with House Republicans. Other Republican contingency options have even less support, leaving open the question of whether the party will unite behind any solution. 

"If the Supreme Court rules, as the law clearly states, that those subsidies don't flow through the federal exchange, we're recognizing the reality that that's going to be a mess," Johnson told Bloomberg earlier this month. "We could be looking at a moment of chaos."

The AAA warns in its analysis that a sudden elimination of the PPACA subsidies could case "massive disruption" in the individual market. If the disruption is severe, "millions of people would drop coverage, and the average costs of those remaining insured would soar."

See also: Court blocks PPACA congressional benefits suit

"I think it's a pretty big concession on our part," Johnson said of his proposalin an interview. Some House conservatives have criticized the idea of continuing the subsidies, even temporarily, as a ratification of PPACA. Johnson, who will likely face a tough reelection battle in 2016, said failing to address the effects of a King vs. Burwell decision ending the subsidies would "of course" endanger Republicans in the election, as Democrats would blame Republicans for causing many Americans to lose their insurance.