There was no rimshot in the Iowa crowd, but former Republican presidential candidate Mitt Romney told a devastating joke at President Barack Obama's expense on Sunday during a campaign stump speech for Iowa Senate hopeful Joni Ernst. The partisan audience stepped on his punchline, but the former Massachusetts governor didn't seem to mind. 'Obama went to the bank to cash a check,' Romney began. 'He didn't have his ID. And the teller said, "You've got to prove who you are." And he said, "How should I do that?" SCROLL DOWN FOR VIDEO . Former Republican presidential nominee Mitt Romney campaigned for Senate hopeful Joni Ernst at an Iowa Farm Bureau event in West Des Moines on Sunday, and brought his best joke to the party . 'She said, "Well, the other day Phil Mickelson came in. He didn't have his ID. So he set up a little cup on the ground, took a golf ball, putted it right into that cup, so we knew it was Phil Mickelson. We cashed the check".' "'And then Andre Agassi came in,"' Romney continued, in the voice of the fictional bank teller, '"and Andre Agassi didn't have his ID either. He put up a little target on the wall, took a tennis ball and a racket, hit it onto that target time and again. We knew it was Andre Agassi, so we cashed his check".' At this point in the story, the teller asks Obama to follow suit. 'So she said, "Is there anything you can do to prove who you are?"' 'And he said, "I don't have a clue." The crowd went wild, thinking that was the end of the joke. But the punchline was yet to come. 'And she said, 'Well, Mr. President, do you want your money in small bills or large bills?'" Ernst, a Republican Iowa state senator and a Lt. Col. in the Iowa Army National Guard, is battling against four-term Democratic U.S. congressman Bruce Braley for the U.S. Senate seat being vacated by longtime Democratic Sen. Tom Harkin. Tanned, rested and ready? Romney, the 2012 White House also-ran, says he's not running for president again – but his poll numbers may be too good for the GOP to leave on the table . The GOP needs to flip six Senate seats to take control of the upper chamber of Congress, and most observers predict it will happen. The Washington Post on Monday gave Republicans a 94 per cent chance of pulling off the electoral feat, which would give them free rein over all of Congress during Obama's last two years in the White House. Ernst leads Braley by a razor-thin 1.2 per cent, according to the average of polls published by Real Clear Politics, but she has been gaining momentum since the end of September.
Romney was stumping for Senate candidate Joni Ernst .
Joke made fun of Obama, suggesting he could be identified without an ID if he admitted 'I don't have a clue'
Former GOP presidential candidate insists he isn't running for office again, but his favorability numbers among GOP voters remain high .
GOP needs to flip six Senate seats on Nov. 4 to take control of both houses of Congress .
There was no rimshot in the Iowa crowd, but former Republican presidential candidate Mitt Romney told a devastating joke at President Barack Obama's expense on Sunday during a campaign stump speech for Iowa Senate hopeful Joni Ernst. The partisan audience stepped on his punchline, but the former Massachusetts governor didn't seem to mind. 'Obama went to the bank to cash a check,' Romney began. 'He didn't have his ID. And the teller said, "You've got to prove who you are." And he said, "How should I do that?" SCROLL DOWN FOR VIDEO . Former Republican presidential nominee Mitt Romney campaigned for Senate hopeful Joni Ernst at an Iowa Farm Bureau event in West Des Moines on Sunday, and brought his best joke to the party . 'She said, "Well, the other day Phil Mickelson came in. He didn't have his ID. So he set up a little cup on the ground, took a golf ball, putted it right into that cup, so we knew it was Phil Mickelson. We cashed the check".' "'And then Andre Agassi came in,"' Romney continued, in the voice of the fictional bank teller, '"and Andre Agassi didn't have his ID either. He put up a little target on the wall, took a tennis ball and a racket, hit it onto that target time and again. We knew it was Andre Agassi, so we cashed his check".' At this point in the story, the teller asks Obama to follow suit. 'So she said, "Is there anything you can do to prove who you are?"' 'And he said, "I don't have a clue." The crowd went wild, thinking that was the end of the joke. But the punchline was yet to come. 'And she said, 'Well, Mr. President, do you want your money in small bills or large bills?'" Ernst, a Republican Iowa state senator and a Lt. Col. in the Iowa Army National Guard, is battling against four-term Democratic U.S. congressman Bruce Braley for the U.S. Senate seat being vacated by longtime Democratic Sen. Tom Harkin. Tanned, rested and ready? Romney, the 2012 White House also-ran, says he's not running for president again – but his poll numbers may be too good for the GOP to leave on the table . The GOP needs to flip six Senate seats to take control of the upper chamber of Congress, and most observers predict it will happen. The Washington Post on Monday gave Republicans a 94 per cent chance of pulling off the electoral feat, which would give them free rein over all of Congress during Obama's last two years in the White House. Ernst leads Braley by a razor-thin 1.2 per cent, according to the average of polls published by Real Clear Politics, but she has been gaining momentum since the end of September.
Republican presidential candidate Mitt Romney speech for Iowa Senate hopeful Joni Ernst. The to prove who you are?"' 'And he said, "I don't have a clue." The crowd went wild, thinking that for president again – but his poll numbers may be GOP needs to flip six Senate seats to take control of the upper chamber of Congress, and