Attorney General Doug Gansler and Delegate Heather Mizeur square off in a televised Maryland Democratic gubernatorial debate in Baltimore. Lt. Governor Anthony Brown declined to participate in the forum. (Katherine Frey/The Washington Post)

The stage for Tuesday night’s Maryland Democratic gubernatorial debate was set with three lecterns. But only two candidates showed up.

The third lectern, positioned smack in the middle, was reserved for Lt. Gov. Anthony G. Brown, who took several hits in his absence: for the botched rollout of the state’s health insurance exchange, for tax increases during his tenure and for allegedly not doing enough to protect state employee pensions.

“The lieutenant governor couldn’t quite make it tonight,” Attorney General Douglas F. Gansler said at one point, before calling the launch of the health insurance exchange “a national embarrassment.”

Brown’s normally active Twitter account stayed silent from 8 to 9 p.m., while the debate was underway. But his campaign released his latest fundraising totals during that hour, saying that since January, he had raised $1.24 million. Brown has $4.15 million on hand for the remaining weeks until the June 24 primary.

Gansler reported having raised only about a quarter as much money as Brown in recent months and said he has $3.1 million on hand. The third candidate, Del. Heather R. Mizeur (Montgomery), said she has about $1 million on hand, including matching money for which she has qualified by participating in the public financing system.

The two-person debate gave Gansler and Mizeur ample opportunity to share their plans for job creation, improving schools and cleaning up the environment — without input from the front-runner.

For Mizeur, it was also a chance to tout her plan to legalize marijuana, an idea both of her rivals have said needs more study.

“Waiting is what happens when you’re not showing leadership,” Mizeur said.

Brown said he was skipping the debate, televised by WBFF-TV in Baltimore, because it violated an agreement among the three campaigns to have only three debates.

His opponents offered a different interpretation of the accord, saying that they agreed to three televised debates — and that a radio encounter in which they and Brown plan to participate does not count.

In an appearance at a senior center about two miles from the debate site, Brown said he was looking forward to the radio debate and another televised one next week in Baltimore. He also took part in the first televised debate, which was held at the University of Maryland on May 7.

“Campaigns are about conversations with voters, and with 28 days to go, we’re working hard to make sure we’re touching as many voters as we can,” Brown told reporters awaiting his arrival at the senior center.

Asked whether he planned to watch the debate, he said, “I don’t think that’s on my schedule.”

Brown’s campaign also chose Tuesday to announce its latest endorsement — from Rep. C.A. Dutch Ruppersberger (D-Md.). The former Baltimore county executive, who considered a bid for governor this year, said Brown is committed to building the state’s business climate.

The debate offered several contrasts between Gansler and ­Mizeur. Gansler touted his plan to gradually reduce the corporate income tax, which he said would help keep employers in the state and attract new ones. Mizeur said the state’s priority should be providing tax relief to small busi­nesses and middle-class Marylanders rather than large corporations.

The candidates took different positions on a new proposal to move the start of the school year to after Labor Day to provide a boost to the state’s tourism industry.

“As a general concept, I think it’s a good idea,” Gansler said, although he added that he would make sure educators agreed.

Mizeur said it was “an interesting concept” but said the decision should be left to local school districts.

Earlier in the day, the running mates of all three Democrats gathered for their own televised debate.

Brown’s running mate, Howard County Executive Ken Ulman, played it safe and largely focused on praising the work of Gov. Martin O’Malley (D) and Brown during their two terms in office. Mizeur’s running mate, the Rev. Delman Coates, talked mostly about electing an outsider who answers to voters rather than the Annapolis establishment.

Gansler’s running mate, Del. Jolene Ivey (Prince George’s), hurled insults at Brown, calling him “a failed leader” on the online health exchange and appearing to question Brown’s decision to send two of his children to parochial school.

“Anthony Brown, he thinks it’s okay to have bad teachers in front of children,” said Ivey, who has five sons. “And that’s probably because his children aren’t in the public schools, but mine are, and I have to worry about, every day, who’s teaching them.”

Brown’s sons attend Catholic school, aides said, but his daughter, now in college, graduated from public school.

The three running mates also sparred on taxes. During O’Malley’s tenure, lawmakers have raised personal income taxes on high earners and increased the corporate income tax, the sales tax, the tobacco tax, the alcohol tax and the gas tax, among others. As a delegate, Ivey routinely voted with a majority of Democrats to support the in­creases.

But Ivey said Tuesday that ­middle-class families have been squeezed too much and that Gansler will ensure that “the lid is on and it will stay on.”

Ulman said he and Brown see “no need for a tax increase in the foreseeable future,” a line they have used throughout the campaign. Coates said he and Mizeur would cut taxes for 90 percent of Marylanders while increasing taxes for the state’s wealthiest residents.

The latest campaign finance reports offer the public its first glimpse of Brown’s and Gansler’s financial strength since January. At that point, Brown’s ticket had nearly $7.1 million cash on hand, compared with about $6.3 million for Gansler’s ticket.

Mizeur, who is participating in the public financing system, has had to file several interim reports.