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Regrets? Mike Ditka has a few.

The former Chicago Bears and New Orleans Saints coach conceded this week that his decision to not run against Barack Obama in the Illinois 2004 Senate race was the "biggest mistake I've ever made."

"Not that I would have won," Ditka said at the grand opening of an oil company in North Dakota, "but I probably would have and he wouldn't be in the White House."

Ditka said Republicans tried to convince him to run for the seat after primary winner Jack Ryan dropped out of the race amidst controversy involving his divorce from TV star Jeri Ryan.

But Ditka, who was a tight-end for the Bears before he coached them to a Super Bowl victory, declined the offer, citing other commitments.

In 2004 Obama commented on a possible race against Ditka, saying, "He's enormously popular. I think if he gets in, he immediately becomes a favorite."

Obama went on to defeat Republican candidate Alan Keyes in a landslide.

Although Ditka, one of only two people to win an NFL title as both a player and a coach, has described himself as an "ultra-ultra-ultra conservative," he has vouched for Democrats in the past, appearing in a campaign ad promoting Illinois governor Pat Quinn in the 2010 election.

And in a 2011 White House appearance, Ditka gave the president a Bears jersey with the number 85 and "Obama" written on the back.