Speaking on Fox News Sunday, Rep. Mac Thornberry, the chairman of the House Armed Services Committee, warned it would be a mistake for President Trump to withdraw from the nuclear deal. Thornberry said he’d opposed the deal initially in 2015.

At this point, however, the chairman noted that losing the deal would greatly erode US leverage against Iran. He noted it would likely mean the end of inspector access to Iran facilities and cost the US visibility on Iran’s civilian nuclear program.

President Trump set a May 12 ultimatum for the deal to be changed, threatening to withdraw if that didn’t happen. With less than a week to go, European efforts to placate him don’t appear to have accomplished much.

Still, Trump is facing a lot of opposition to the idea of withdrawing from the pact. This is not just international opposition, but domestically, a growing number of members of both parties believe the US killing the deal just a couple of years after it was made would do severe harm to US credibility, and provoke a backlash against the US, not Iran.