Sen. Ted Cruz’s bill to forbid an Iranian diplomat from entering the U.S. got President Barack Obama’s signature Friday, though the president noted he still considers the law “advisory.” The law spearheaded by the typically polarizing Texas Republican was a rare moment of consensus in D.C.: Obama’s sign-off follows unanimous passage in the Senate and House last week.

When Iranian militants seized the United States Embassy and took dozens of Americans hostage on an overcast Sunday morning in November 1979, I assumed it was just a brief anti-American sit-in. My main concern, I told my editors at Newsweek, was not how dangerous Tehran would be.