Barack Obama’s history of marijuana and cocaine use offers a potent attack point for Republicans if he ever becomes the Democratic nominee for president.

Although the Obama campaign wants to dismiss the subject as a Clinton campaign tactic, Bill Shaheen, Hillary’s New Hampshire campaign chair, was right to point out Obama’s vulnerability on this issue.

In an interview with the Washington Post, Shaheen warned of the potential political consequences of Obama’s past drug use:

“The Republicans are not going to give up without a fight … and one of the things they’re certainly going to jump on is his drug use,” said Shaheen, the husband of former N.H. governor Jeanne Shaheen, who is planning to run for the Senate next year. Billy Shaheen contrasted Obama’s openness about his past drug use — which Obama mentioned again at a recent campaign appearance in New Hampshire — with the approach taken by George W. Bush in 1999 and 2000, when he ruled out questions about his behavior when he was “young and irresponsible.”

Shaheen said Obama’s candor on the subject would “open the door” to further questions. “It’ll be, ‘When was the last time? Did you ever give drugs to anyone? Did you sell them to anyone?'” Shaheen said. “There are so many openings for Republican dirty tricks. It’s hard to overcome.”

As I commented in a recent posting, Obama’s non-response to questions about drugs at a Manchester, NH, high school visit makes me question his moral leadership. Although he again discussed his own past drug use, he had nothing to say to students about the perils of drugs or the options they have if they need help overcoming alcohol or drug addiction. To me, the visit was an opportunity to offer students some important guidance on the issue; instead, Obama passed.

More on Shaheen’s comments can be found at the New York Times.