U.S. President Donald Trump said the prospect of global economic collapse was a big reason he signed an interim peace deal with Iran. But that admission exposes a key U.S. weakness.

The memorandum of understanding that Trump signed on Wednesday reopened the Strait of Hormuz and set in motion waivers for sanctions on Iran¡¯s oil sales to the international market. The effect was immediate: The price of oil tumbled further and U.S. stocks rose, facts that Trump pointed out at a news conference in France last week.

¡°I didn¡¯t want to see economic catastrophe,¡± Trump said at a news conference in Evian, France on Thursday. ¡°If you kept this going, that could¡¯ve happened.¡±