Unacceptable topics for negative campaigning:

• Honest mistakes: For example, when Obama at one point said he had visited 57 states or the time when McCain said he didn't know how many houses he owned. "There are honest mistakes politicians make in the course of campaigns." (Others are probably less charitable on those examples.)
• Things that are untrue: For example, the rumor that Michelle Obama had used the word "whitey" in a speech. "She didn't," Ehrlich said. "That was simply untrue and unfair."
• Things that are misleading: "The Obama campaign has taken what John McCain has said about Iraq that we might ahve a Korea-type situation" and be there for 100 years out of context. Or, "Sen. Obama originally said he would have no preconditions for sitting down with terrorists, and he changed his mind, but he's still being attacked for his original position. That's not fair." (The Obama folk would probably argue that Ehrlich is misstating their original position, too, but you get the point.)
• The perjorative or personal: "How you're raising your kids, your sex life how you run your home. That stuff is incredibly personal. Attacks on the purely personal are nobody's business, even if you're in public life."
• Things that are just plain mean: "Barack Hussein Obama. That would be fair if the man went by his middle name. He doesn't. If you hear that, you know it's meant to be negative." Or, Ehrlich said, making fun of McCain for his physical limitations related to injuries suffied while a POW in Vietnam. "To attack a man based on that is beyond disgraceful, and I've heard bad jokes along those lines." Or the suggestion that "the only thing Sarah Palin brought to the ticket is the fact that she didn't have an abortion."

Close calls:

• Divorce and cheating
• Public vs. private character
• Old news (such as attacking Michelle Obama based on the views on race she expressed in her college thesis).
• Credit problems: "You have credit problems when you're younger, and 20 years later, you want to be the chief executive of a $30 billion budget. Is that fair? Is that relevant?"
• Drug use: "I went to college in the '70s. I didn't use drugs, but a lot of my friends did."

The deciding factors in those cases, he said, are the gravity of the offense, the proximity in time and the frequency of the offense.

Ehrlich asked me to throw out the first question after his lecture, so I asked whether he thinks it would be fair for McCain to cut a negative ad based on Obama's former pastor, the Rev. Jeremiah Wright. The class, asked for a show of hands, was pretty split on the issue. Ehrlich came down, more or less, against it.

The former governor launched into a fairly lengthy defense of Obama, noting that he's a charismatic political figure and a dedicated family man. He said he would perhaps run a negative ad about a variety of Obama's associates, "not in making the case that he's a bad guy" or to suggest that Obama buys into the "god damn America" rhetoric of Wright. "I don't think he does. But I think he's coming from the pretty hard left," as evidenced by the friends he keeps, Ehrlich said.

So, after all that, has Ehrlich practiced what he preaches about negative campaigning? What about Martin O'Malley?