President Barack Obama had barely finished proposing an idea to deal with a far-reaching Supreme Court decision on Obamacare before Republicans fired back with a categorical response: Not gonna happen.

At the G7 conference in Germany on Monday, the president said if the justices strip subsidies from millions of Americans, “Congress could fix this whole thing with a one-sentence provision” making clear that Healthcare.gov subsidies are available in all 50 states. Republicans quickly fired off a rebuttal.

“Let’s be clear: if the Supreme Court rules against the Administration, Congress will not pass a so called ‘one-sentence’ fake fix,” Wyoming Senator John Barrasso, who is leading Republican efforts to craft a contingency plan, said in a statement.