The question was when, not if, Doug Duncan would start throwing punches during Wednesday night’s first joint appearance of candidates for Montgomery County executive.

Popular two-term incumbents usually don’t go down by themselves, and Duncan, who is competing in the June Democratic primary to reclaim the job he held from 1994 to 2006, knows it. He consequently took every opportunity to depict County Executive Isiah Leggett as weak and ineffective, especially when it came to securing school funding from Annapolis.

“We need a stronger leader,” Duncan told a small audience that braved the snow and the forecast to attend the forum, which was held at Richard Montgomery High School and sponsored by the Montgomery County Education Association and other unions.

Calmly but firmly, Leggett gave as good as he got, dismissing Duncan’s version of recent county history as “a parallel universe.” Money was easier to find in the go-go economy that existed during much of Duncan’s three-term tenure, he said.

“The good old days are gone,” Leggett said. “It is the real days today.”

Duncan came prepared to make school overcrowding and construction issues the centerpiece of his attack. Leggett and the county’s state legislative delegation are seeking a major funding package from the General Assembly to address huge enrollment growth in the 151,000-student system. Duncan devoted much of his five-minute closing statement to faulting that effort, suggesting that Leggett, and to a lesser extent council member Phil Andrews (D-Rockville-Gaithersburg), waited until an election was looming to pursue it.

“This is a problem we’ve known about for several years,” Duncan said. “What took you so long?”

Duncan also said Leggett failed to hold Gov. Martin O’Malley (D) accountable for allegedly breaking a promise to provide extra school construction funding to Montgomery during the 2008 legislative session.

In exchange for Leggett’s help during the 2007 special session in building support for tax increases and a referendum on legalizing slot machine gambling, O’Malley was supposed to deliver $50 million, Duncan said. Instead, an interagency committee of O’Malley appointees recommended $46 million.

“We just sat back and said, ‘Thank you very much,’ ” Duncan said. “We should have held him accountable.”

How much of a bargain had been struck isn’t clear. The Washington Post reported at the time that “recollections differ”over the degree to which O’Malley actually committed the extra money to Montgomery — an amount the Post article said was $55 million.

In his 2007 State of the County speech, Leggett talked about “receiving as much as $55 million from the state to help meet our critical school construction needs in next year’s budget.” During Wednesday night’s forum, and in comments later, Leggett professed no memory of any such failed deal.

Duncan also criticized Leggett for going along with last year’s push by O’Malley and the General Assembly to pass a major school construction funding bill for Baltimore city schools. Duncan said that, instead of agreeing to support Baltimore legislators in exchange for their backing to increase the gasoline for transportation improvements, Leggett should have insisted on a statewide school construction program.

“We’re in this mess because of a lack of leadership by my two primary opponents,” Duncan said.

“I think we need a little bit of reality,” Leggett responded.

He scoffed at the notion that he could somehow dictate terms to the governor. He also said that the city of Baltimore and Montgomery County have completely different needs when it came to school construction. Baltimore’s system was in dire physical condition, Leggett said, and supporting the city’s package was “the right thing to do.”

Leggett framed the larger issue as Duncan’s triumphal view of his own record, which he said ignores profligate spending that placed the county in a serious financial hole even before the Great Recession.

“When I assumed this office [in 2007], the county was broke and getting broker,” Leggett said, referring to large deficits that he and the County Council had to close.

Leggett touted significant increases in capital spending for schools during his tenure, along with reductions in emergency response times, advances in affordable housing and record cash reserves as proof of the sound management ability he brought to the job.

“We’ve made tremendous progress,” he said.

The heavyweight bout between Duncan and Leggett, who between them have held the county executive’s job for the last 20 years, made it tougher for the two other contenders, Andrews and Republican James Shalleck, to make their mark.

Andrews has never been a teachers union favorite because of his outspoken opposition to large salary increases and the state’s “maintenance of effort” funding requirements for school systems.

He touted his sponsorship of the “living wage” law for county contractors, a ban on restaurant smoking and his latest initiative, to establish public funding for county campaigns. Andrews does not accept donations from developers or union PACs.

He had his best moment when he talked about the influence of big money and special interests on county government.

“The county executive needs to remember who’s not in the room,” Andrews said, “who doesn’t have a PAC and who doesn’t have a lobbyist to represent them.”

Shalleck, a blunt-spoken ex-prosecutor originally from New York, is running unopposed — and without illusions — for the Republican nomination in a county where Democrats hold a 3-to-1 advantage.

He sounded more like a free-spending Democrat as he talked about what he called the “big vision stuff” he would bring to the county if elected, including a four-year university and minor league sports teams. He also promised to sell off and privatize the county’s system of liquor stores.

Shalleck called for a “uniform police presence” in all county public schools to prevent the kind of catastrophic schoolhouse violence that some other U.S. communities have seen.

“I don’t want to see a CNN helicopter flying over this school,” he said.