President Trump plans to sign an executive order that would remove the right to citizenship for babies of non-citizens and unauthorized immigrants born on U.S. soil, he said yesterday in an exclusive interview for “Axios on HBO,” a new four-part documentary news series debuting on HBO this Sunday at 6:30 p.m. ET/PT.

Why it matters: This would be the most dramatic move yet in Trump’s hardline immigration campaign, this time targeting “anchor babies” and “chain migration.” And it will set off another stand-off with the courts, as Trump’s power to do this through executive action is debatable to say the least.