Aides to President Donald Trump are drafting plans to condition U.S. aid to other countries on how well they treat their religious minorities, two White House officials said.

The proposal is expected to cover U.S. humanitarian assistance, and could also be broadened to include American military aid to other countries. If the proposal becomes reality, it could have a major effect on U.S. assistance in a range of places, from Iraq to Vietnam. Its mere consideration shows how much the White House prioritizes religious freedom, an emphasis critics say is really about galvanizing Trump’s evangelical Christian base.

But experts on U.S. aid also warn that picking and choosing which countries to punish could be a very difficult task, not least because several countries that are partners or allies of the United States have terrible religious freedom records.

The effort comes as Trump faces an impeachment inquiry that hinges in part on whether he froze military aid to Ukraine as a way to pressure its government to investigate his political rivals.

Two White House officials confirmed the basics of the religious freedom aid-conditioning plan. They stressed that the idea is in its early stages and an executive order is still being drafted, meaning questions about, say, whether military aid will be covered remain unanswered.