DES MOINES, Iowa — Ted Cruz is out with a new ad attacking Donald Trump’s “New York values.” The ad includes a 1999 video of Trump saying he was pro-choice, and it also replays Trump’s notorious “How stupid are the people of Iowa?” line from a speech in Fort Dodge last November, when Trump mused on how Iowa voters could possibly support the now-faded candidacy of Ben Carson.

It’s an effective attack. And now, it highlights how critically important, and perhaps downright fortuitous, it was for Trump to arrange an appearance a few days ago with Chuck Grassley, Iowa’s highly respected Republican senator who might just as well be known as Mr. Iowa Values. Thanks to Grassley’s evenhandedness, Trump has an effective comeback to Cruz’s attack.