Evan Vucci, Associated Press
Rain falls on Capitol Hill in Washington, Monday, Oct. 7, 2013.

WASHINGTON — Senate Finance Committee Chairman Orrin Hatch is backing a Supreme Court challenge to one of the keystones of President Barack Obama's health care law. Now, he says he's preparing a plan to help people who might be hurt if his side wins the case.

The Supreme Court is scheduled to hear arguments next week in a case by conservatives and Republicans that says many subsidies the law provides for millions of people are unconstitutional. They argue that the law only allows such subsidies for the 13 states that set up their own marketplaces to sell health insurance, not the 37 states that use the federal HealthCare.gov website.

Democrats say the subsidies were supposed to go to people buying policies on either the federal or state marketplaces.

Should the court uphold the suit — a decision is expected in June — millions of people could be forced to drop their health coverage because those subsidies make their insurance affordable.

So on Monday, Hatch, R-Utah, told an audience at the conservative Heritage Foundation that he will release "a short-term solution for those Americans that may be affected by the decision" in that case.

Hatch provided no details on what he might propose or when it would be ready. Talking later to reporters, he suggested it might have to last until, he hopes, a Republican moves into the White House in 2017.

GOP support for such a proposal is unclear. One likelihood — negotiations with Democrats in the aftermath of such a verdict would be complex.