On the radio, Gansler also took aim at how well Brown oversaw preparing the state for the Base Realignment and Closure Process, known as BRAC. The process brought tens of thousands of military jobs to Maryland over the past few years through expansions at Fort Meade in Anne Arundel County and at Aberdeen Proving Ground in Harford County.

"BRAC ... was an unmitigated disaster in terms of infrastructure being built, roads, jobs," and a missed opportunity, Gansler said on the Steiner show. "Everyone who came here for BRAC is now going back to the states where they came from, and we haven't really benefited economically from that at all."

Whether Brown's leadership in the BRAC process was successful is far from clear-cut, but several participants from affected communities disagreed with Gansler's assessment that it was a total flop.

Michael Bennett, who has been mayor of Aberdeen since 2007, dismissed the statement as "campaign rhetoric." Bennett, a Democrat, has endorsed Brown, largely because of the lieutenant governor's handling of BRAC.

"He was absolutely engaged in that process," Bennett said. "He did a really excellent job."

Robert Leib, who retired in July as BRAC coordinator for two Republican administrations in Anne Arundel County, said Brown was "a strong advocate for Maryland" in dealings with the federal government about the expansion at Fort Meade, but less effective in getting the state to change its transportation priorities.

"Brown didn't botch it, but there was so much more that could have been done if Maryland had been more aggressive," Leib said.

Kromer, the political scientist, said the vitriolic exchanges between Brown and Gansler could open a path for the third candidate in the race, Del. Heather R. Mizeur of Montgomery County. But so far, Mizeur's underfunded campaign hasn't found it, Kromer said.

"She's run a clean campaign. She hasn't made any real flubs. She just hasn't been able to gain that traction," Kromer said.

Mizeur's campaign declined to comment on the most recent exchange between the other Democrats in the race.

Baltimore Sun reporter Jeff Barker contributed to this article.