With every passing day the agreement in respect of Gaza is starting to look like President Trump’s worst deal. The 47th president isn’t the only one to bear some responsibility for what is shaping up as a fiasco. President Biden claims that it follows a structure he proposed in May. Mr. Trump played a role in bringing the deal about, though, and has sought to claim some, if not all, of the credit. It’s about a deal that he could all too soon regret.