"It was my idea to withdraw," Richardson said when asked whether Obama's transition team pressured him to drop his nomination out of concern for the federal investigation into how his political donors landed lucrative transportation contracts in his state.
The governor, speaking publicly for the first time about the sudden move, stood by his claim that he only took his name out of the running because he was concerned the investigation would last longer than he originally anticipated. The inquiry centers on CDR Financial Products, which won state contracts for $1.48 million.
"I had hoped that the CDR investigation would have concluded in December with a clean bill of health for my administration," Richardson said. "Since the investigation was not finished in December and, as long as the CDR investigation is ongoing, I made the decision to withdraw as the president-elect's nominee for commerce secretary rather than ask for a delay in my appointment."
Richardson read from a prepared statement but wouldn't address the grand jury that is looking into possible "pay-to-play" dealings.
The Democratic governor said he didn't want to jeopardize the process by commenting on the investigation. He said he has "faith in the criminal justice process, and we must allow it to run its course."
He said his attention will be on New Mexico and the upcoming legislative session and encouraged the national picture to focus on people who are losing jobs, savings and their homes in this country.
"That's the real tragedy. You know, mine is minor compared to that," Richardson said.
The New Mexico governor created a gap in Obama's mostly smooth and speedy transition process when he backed out of the Cabinet.
Richardson, who insists he'll be cleared of wrongdoing, issued a written statement Sunday saying the inquiry would force an "untenable delay in the confirmation process."
But the withdrawal raises questions about how much Obama's transition vetting team knew about the severity of the investigation before the president-elect announced Richardson as his commerce pick on Dec. 3.
A senior Obama adviser said Richardson gave assurances before he was nominated last month he would come out fine in the investigation. But as the grand jury pursued the case, it became clear that confirmation hearings would be delayed at least six weeks until the investigation was complete, said the adviser, speaking on condition of anonymity about the discussions because they were private.
Aides to both men insisted Richardson made the decision to withdraw and was not pushed out by Obama. But one Democrat involved in discussions over the matter said transition officials became increasingly nervous during the last couple of weeks that the investigation could become an embarrassment to Obama, who ran on a clean government pledge.
The New Mexico investigation would be the second "pay-to-play" inquiry that has touched the Obama transition process.
Just a few days after Richardson was nominated, Illinois Gov. Rod Blagojevich was arrested on federal corruption charges and accused of trying to sell off Obama's vacant Senate seat and engage in other "pay-to-play" schemes. Obama and his aides have not been implicated in that case, but the issue has created a distraction for the president-elect as he tries to negotiate a new economic stimulus proposal in the run-up to taking office.
Richardson spokesman Gilbert Gallegos said the governor believed the investigation would be resolved by this time, but decided to withdraw when it became clear it would not.
The Associated Press contributed to this report.