So President Obama walks into a bank …

Mitt Romney’s got jokes.

The 2012 Republican presidential nominee had some fun at President Obama’s expense over the weekend while campaigning for GOP Senate candidate Joni Ernst in Iowa.

{mosads}”Now when you run for office, people tell you you shouldn’t tell jokes,” Romney said, according to the Washington Free Beacon. “But I’m not running for office, so I can tell one.”

The former Massachusetts governor then launched into his story:

President Obama went to the bank to cash a check and he didn’t have his ID. And the teller said you’ve got to prove who you are.

He said, “How should I do that?” She said the other day Phil Mickelson came in, he didn’t have his ID but he set up a little cup on the ground, took a golf ball, putted it right into that cup so they knew it was Phil Mickelson. They cashed his check.

And then Andre Agassi came in. And Andre Agassi didn’t have his ID either. He put a little target on the wall, took a tennis ball and racquet — hit it onto that target. We knew that was Andre Agassi so we cashed his check.

And she said to him, “Is there anything you can do to prove who you are?” And [Obama] said, “I don’t have a clue.”

And she said, “Well, Mr. President, do you want your money in small bills or large bills.”

Ernst is locked in a tight race with Rep. Bruce Braley (D-Iowa) to replace retiring Sen. Tom Harkin (D)