The third and perhaps final debate between Gov. Martin O'Malley and former Gov. Robert L. Ehrlich Jr. ended without any knockout blows. Both men argued their positions well on health care, education, economic development and other issues. Even the stylistic differences between the more improvisational Mr. Ehrlich and the more focused Mr. O'Malley were muted in this debate compared to their previous two. This one will likely go down as a Rorschach test — if you tend to agree with Mr. Ehrlich, you'll think he won, and if you tend to agree with Mr. O'Malley, you'll think he did.

But given the setting, Mr. Ehrlich needed to come away with a lot more than that. The debate was on former state Sen. Larry Young's radio show on WOLB-AM, which reaches a predominantly African-American audience. Mr. Ehrlich has been making overtures to the black community for years — in 2002, the only debate was sponsored by the NAACP; he selected an African-American running mate that year; and, as he pointed out during yesterday's debate, he's no stranger to shows like Mr. Young's. But it hasn't made much difference in terms of political support; the most recent public poll of the governor's race, released this week by Gonzales Research and Marketing Strategies, found that Mr. O'Malley is leading Mr. Ehrlich among African-Americans 82 percent to 8 percent, with the rest undecided or favoring third-party candidates.

Mr. Ehrlich trying to win support in that audience is a bit like Mr. O'Malley debating him in front of the Arbutus Republican Club — to win, he needed to do more than hold his own, he needed to fundamentally change the way listeners thought about Mr. O'Malley.

The strongest point Mr. Ehrlich has in that effort is Mr. O'Malley's pursuit of zero-tolerance police strategies during his time as Baltimore mayor. Mr. Ehrlich accuses Mr. O'Malley of locking up thousands of African-Americans for minor offenses — if any reason at all — only to see them released without any charges being filed. That, he said, is a violation of their constitutional rights and will forever hinder their ability to get jobs.

He has a point. The American Civil Liberties Union and the NAACP sued the city over the practice and this summer won an $870,000 settlement that requires an outside auditor to monitor "quality of life" arrests in Baltimore for the next three years.

Still, the political value of the issue is questionable. Mr. Ehrlich tried this argument in 2006, and in a more forceful way; attorney Billy Murphy, who is African-American, cut a radio ad for the Republican in which he said, "O'Malley's police falsely arrested 21,175 black people in 2005 alone, and none of these 21,175 black people were ever, ever charged with a crime, and he's been doing this to us for seven years. How can any black person with any degree of self respect support a man who does this to us?" In spite of that, black voters turned out in record numbers, according to exit polls, and supported Mr. O'Malley by better than a 4-to-1 margin.

But what about the substance? Mr. Young, despite generally doing a good job in the debate at getting the candidates to talk about issues they haven't addressed before, let Mr. O'Malley off the hook on mass arrests. Mr. Young made it the first question he asked, but he didn't press the governor when he veered instead into a discussion of drug treatment. But Mr. O'Malley did at least hint at a reasonable answer: Things were so bad in the city in 1999 that Baltimore's residents, black and white, were willing to try almost anything to bring the crime rate down.

The legacy of zero tolerance is that it was successful in the beginning but that its utility was limited. Under former Police Commissioner Ed Norris, the city cleaned up open-air drug markets and brought the annual homicide rate under 300 for the first time in a decade. Under subsequent commissioners hired by Mr. O'Malley, progress stalled and started to reverse until the current commissioner, Frederick H. Bealefeld III, was appointed by then- Mayor Sheila Dixon. He has instituted a more nuanced strategy that seeks to simultaneously crack down on the worst offenders and build support in the community. But whether Mr. Bealefeld's approach would have been as successful in the Baltimore of 1999 is impossible to know.

Mr. Ehrlich's point about the lingering effects of the policy misses a key development that has taken place since he left the governor's mansion. In 2007, Del. Keith Haynes of Baltimore successfully pushed through legislation to automatically expunge the criminal records of people who were arrested but not charged. That resulted in thousands of expungements in Baltimore in the first year alone. In 2008, Del. Samuel I. "Sandy" Rosenberg, also of Baltimore, successfully sponsored a bill allowing those convicted of nuisance crimes such as loitering and drinking alcohol in public to petition to have those records expunged. Mr. O'Malley supported both bills.

But the questions Mr. Young asked were a reminder that the African-American community in Maryland is large and diverse. As inflammatory as the question of mass arrests is, it may not outweigh health care reform, college tuition, K-12 education or other issues that are important to black and white voters alike. And as Mr. O'Malley and Mr. Ehrlich suggested in their eagerness to back the idea of an arts district on Liberty Road in Baltimore County's Randallstown community, African-American voters are considering a lot more than urban issues as they make up their minds.

Both candidates did their share of pandering — Mr. Ehrlich practically patted himself on the back for being a Republican willing to debate on black radio, and Mr. O'Malley made markedly more references to his support for President Barack Obama than he did in other debates. But on the substance, neither candidate offered much that was new, and for Mr. Ehrlich, in this forum, that wasn't enough.