Martin O’Malley's leading supporters left an afternoon gathering in Baltimore on Monday more convinced than ever that he will move forward with a 2016 presidential bid, several participants in the event said.

The former Maryland governor, who’s said he will probably make a decision by May, huddled with more than 150 donors and other boosters at the Baltimore Hilton for what was billed as an “issues conference.” The event was closed to the press and included discussions about foreign policy, health care and education.

Though O’Malley said nothing explicit about his plans, those in attendance said his upbeat nature and assessments offered by top political aides gave them the distinct impression that he is willing to challenge Hillary Rodham Clinton for the Democratic nomination, however long the odds.

“I think he’s energized by the reception he got this past weekend in Iowa,” said Rob Werner, a supporter from New Hampshire who came down for the gathering Monday. “I think he’s poised to do it, to get in the race. He certainly seems to be heading in that direction.”

Senior members of O’Malley’s political team made presentations, participants said, and a speech by O’Malley echoed the populist addresses he gave in Iowa, the nation’s first presidential caucus state. O’Malley aides said the former governor plans to give several policy speeches in coming months to flesh out his agenda.

On recent trips to South Carolina, New Hampshire and Iowa, O’Malley has been aggressively trying to position himself as a more progressive, forward-looking alternative to Clinton. At the same time, some Democrats have started looking more seriously for other options in the wake of recent controversies over Clinton’s use of a private e-mail account as secretary of state and foreign donations to the Clinton Foundation.

“A month or so ago, there was a view that Hillary’s it,” said Phil Noble, a longtime Democratic activist in South Carolina who’s known O’Malley for more than 30 years. “Now, there’s a view that there is room for an alternative, and O’Malley’s on the radar screen.”

At Monday's gathering, Clinton’s name wasn’t really part of the conversation, said Terry Lierman, a former chairman of the Maryland Democratic Party who has helped raise money for O’Malley’s political action committee.

“That name was not mentioned at all today,” Lierman said. “It was about Martin and what his vision is and where he thinks the country should be going.”

While most of those in attendance were longtime O’Malley boosters, some said they remain undecided about a 2016 White House hopeful, including Vincent Sheheen, the unsuccessful Democratic nominee for governor of South Carolina  in 2010 and 2014.

“I guess I came up here to see if [O’Malley] is serious, and I came away with the impression that he’s very serious,” Sheheen said. “I think he’s a legitimate candidate and contender.”

O’Malley plans to be in New Hampshire next Tuesday for a “Politics & Eggs” address to business and political leaders, a Granite State tradition that is considered a rite of passage for White House hopefuls. It will be his second trip this month to the state that holds the first presidential primary. And he’s booked to be back in Iowa in early April, with an itinerary that includes a speech to the Polk County Democrats in Des Moines.