Following comments suggesting Republicans might use Barack Obama's past statements on his own drug use against him in a general election, former New Hampshire Democratic Party chair and former New Hampshire First Gentleman Bill Shaheen has stepped down as chairman of Hillary Clinton's campaign in the state.

"Senator Clinton has been running a positive campaign focused on the issues that matter to America's families. She is the best qualified to be the next President of the United States because she can lead starting on day one. I made a mistake and in light of what happened, I have made the personal decision that I will step down as the Co-Chair of the Hillary for President campaign," Shaheen said in a statement emailed from the campaign.

Shaheen was one of the most sought-after endorsements in New Hampshire earlier this year. His choice to back Clinton was heralded as a major victory, lending her a big name with loads of experience working in politics in the state. In an interview with the Washington Post, Shaheen suggested that Obama's past would come back to haunt him. "It'll be, 'When was the last time> Did you ever give drugs to anyone? Did you sell them to anyone?'" he said, per the Post. "There are so many openings for Republican dirty tricks. It's hard to overcome."

Shaheen issued an apology earlier today.