Van Jones, President Barack Obama's green jobs czar, has resigned amid a furor over his past statements regarding the Bush administration and the September 11 terrorist attacks.
In a resignation letter released by the White House just after midnight on Sunday, Jones said he was the victim of a smear campaign.
"On the eve of historic fights for health care and clean energy, opponents of reform have mounted a vicious smear campaign against me. They are using lies and distortions to distract and divide," he wrote
The Washington Times quoted Jones as saying that while he was getting encouragement from both political parties to "stay and fight," he "cannot in good conscience ask my colleagues to expend precious time and energy defending or explaining my past."
"We need all hands on deck, fighting for the future," he said, adding in the letter for Council on Environmental Quality Chairman Nancy Sutley that he has been honored to serve the president.
Sutley issued a short statement thanking Jones for his work and calling him a "strong voice for creating 21st century jobs that improve energy efficiency and utilize renewable resources."
Politicians had been calling for Jones to resign after it was revealed in recent days he signed a petition supporting 9/11 conspiracy theories and has made other unflattering statements caught on video.
White House press secretary Robert Gibbs offered a less-than-stellar endorsement of Jones on Friday.
The holiday weekend release was used by many politicians to lessen bad publicity.