The planks have traditionally been a way for social conservatives to flex their muscles–and often have little impact on the nominee’s positions: Bob Dole acknowledged in 1996 that he didn’t even read the whole platform, and publicly rejected immigration and abortion provisions he deemed to be too conservative.

But the concern with Trump isn’t so much about his differences as it is with his inconsistencies and at times undefined positions. The presumptive Republican nominee prides himself on being “flexible,” a trait that carries appeal among many voters but that creates some anxiety among party leaders hoping to forge consensus on an overall agenda.

“For the Republican Party, it’s very important to get the platform right and hold on to the conservative gains in the document,” says Matt Schlapp, president of the American Conservative Union. “How Donald Trump handles the platform will send a very loud statement to conservatives, especially those who have not yet endorsed him. It’s important, symbolic and a big step that Trump needs to get right.”

The broader GOP general election agenda figures to be center stage at a highly anticipated meeting Thursday between Trump, House Speaker Paul Ryan and Republican National Committee Chairman Reince Priebus in Washington.