Republican leaders are coalescing around a plan to extend the health law’s tax credits for as long as two years, while repealing other parts of the law, if the Supreme Court invalidates the credits.

The high court is expected to rule by the end of June on whether to restrict the 2010 law’s tax credits—used by low- and moderate-income consumers to help pay their insurance premiums—to the handful of states that opted to set up their own insurance exchanges.