With no credible opponent challenging Mayor Muriel E. Bowser (D) for reelection, the campaign’s most scintillating drama may be whether a man who says he sleeps on sidewalks, buses and in homeless shelters can qualify for the ballot.

Jeremiah Stanback, 32, believed that he had earned a spot on the city’s political stage when he submitted 2,040 nominating signatures to the D.C. Board of Elections — 40 more than what is required of mayoral candidates for the city’s Democratic and Republican primaries in June.

But two other candidates — themselves little-known — challenged the validity of Stanback’s signatures, forcing him to show up before a mediator Wednesday and fight for a spot on the ballot.

“They’re trying to crucify me!” said Stanback, wearing a button-down shirt, overcoat and Redskins cap as he sat in a reception area before a hearing at the board’s headquarters. At his feet was a duffel bag containing clothing and other personal items that he lugs with him across the city.

“These people want to make me fail,” he said. “I came with all these aspirations, but I’m homeless and they don’t want that.”

Stanback, who calls himself “The Homeless Candidate,” says he wants to expand affordable housing in the District, which has one of the highest rates of homelessness of any U.S. city. When Bowser ran four years ago, she pledged to address homelessness as one of her signature issues.

As he waited for his hearing, Kelly Turner, a voter-services assistant, looked over at Stanback from her nearby desk and encouraged him to eat the egg sandwich that lay unopened in silver foil on his lap.

“You’re not supposed to have any food in here, but I want you to eat,” Turner told Stanback before reassuring him that his quest to qualify for the ballot was not without merit.

“You did really well,” she said.

In recent months, Stanback has become a familiar face at the election board’s Southeast office, as well as streets and at Metro stops across the city, as he has gathered signatures to run in the Democratic primary in June.

“Hi! I’m Jeremiah Stanback! Running for mayor!” he often announced in a gravelly, booming voice, clutching his petitions and a pen as he marched toward strangers.

Stanback said he spent the night before his hearing beneath an outdoor table at a shuttered downtown restaurant, after having nodded off on the 70 bus, which he said was jammed with passengers who do not have permanent addresses.

“It was like a ‘Ride Hotel,’ ” Stanback said. “At 2 a.m., it was packed. There were so many people I couldn’t take it anymore.”

If he was feeling tired, Stanback did not show it when he arrived for mediation. He aimed his ire at Rudolph McGann, an elections board attorney who presided over the hearing.

“You have got to slow down,” he said as McGann tried to explain that mediation was about to begin. “You’re rolling like you had two cups of coffee.”

The challenge to his petitions was filed by another mayoral candidate, Ernest Johnson, who was represented by three silent surrogates.

An assistant Board of Elections registrar, Deanna Smith, informed Stanback that Johnson had questioned 385 of his signatures. The board, she said, now considered 1,755 of his signatures valid — or 245 fewer than what he needed to qualify.

McGann told Stanback he had to decide whether to withdraw his candidacy or ask for a formal hearing of the Board of Elections to settle the dispute.

At one point, the board officials pointed out that Stanback could run as a write-in candidate, as no less than former mayor Anthony Williams had done in 2002 after his nominating petitions were found to be riddled with fraud.

As he considered his answer, Stanback delivered a monologue, at various points sharing that he was gay and homeless, that he could be a bit “theatrical,” and that no one would stop him from achieving his goal.

“I’m going to be the mayor,” Stanback promised. “You may not like it.”

McGann urged Stanback to keep his attention on the pertinent legal issues.

“Don’t talk to me like I’m a child,” Stanback countered. “You’re being very condescending.”

“Mr. Stanback,” McGann said, “what do you want to do with this matter?”

Stanback turned to him and asked: “If you were in my shoes, what would you do?”

“I can’t do that, sir,” McGann replied. “I can’t direct you.”

“What would you do?” Stanback insisted.

“I wouldn’t run for office,” McGann answered.

McGann excused Ernest Johnson’s surrogates, who were replaced by Stanback’s second challenger, James Butler, who is also running for mayor.

Butler had questioned 141 of Stanback’s signatures. But moments after beginning the mediation, Butler announced that he had “rethought my strategy” and withdrew his challenge.

Butler stood and left the hearing room, later explaining that “everyone has a right to run . . . and it’s simply good for democracy to give the voters a choice.”

Stanback remained in his seat, considering his options.

“Either you withdraw or take it to the board,” McGann reminded him.

Moments later, Stanback said he had reached a decision: He would not be a candidate in the Democratic primary.

But he was not done with mayoral politics.

“I’m going to run as an Independent, baby!” he proclaimed, his smile wide.

He will need 3,000 fresh signatures to qualify for the November ballot, the board officials told him. The deadline is Aug. 8.

“I won’t rest,” Stanback replied. “I will be the mayor.”