Julius Henson, the architect of the robo-calls in the 2010 Maryland governor’s race that attempted to suppress black turnout on Election Day, is now running for state Senate. (Andre Chung/For The Washington Post)

As midnight approached on a recent Sunday night, Nathaniel J. McFadden, a veteran Maryland state senator, was getting into bed. Meanwhile, the man plotting his demise was traveling through East Baltimore, placing on car windshields thousands of bright red fliers eviscerating his record.

“McFadden’s Dirty Dozen,” read the headline above 12 pointed questions and their equally pointed — if undeniably slanted — answers: “Did McFadden vote to raise taxes and fees forty times in the past seven years?” Answer: Yes. “Is McFadden healthy enough to give the position the time and energy required?” No. “Can you name one positive thing McFadden has done for you or your community?” No.

This snarling tone has made the flier’s author, Julius Henson, one of Maryland’s most infamous political operatives, a man who once described himself as a “pure warrior” who’s “supposed to do you in, out of the gate.”

Henson is best known, perhaps, for being jailed after writing a robo-call script for Republican Robert Ehrlich’s 2010 gubernatorial campaign that prosecutors have said was intended to discourage blacks from voting.

But now, Henson isn’t hatching attacks for others. Barred from consulting for campaigns because of the robo-call conviction, he has reinvented himself as a candidate and is challenging McFadden, a 20-year incumbent and the Senate’s former majority leader.

“This boy is going to lose,” Henson said the day after distributing his fliers throughout East Baltimore. “He knows he’s going to get whooped. Whoop him like he stole something.”

Each of the General Assembly’s 188 seats is up for election in 2014, but few races will capture more attention than the one in the predominantly black 45th District, if only because of Henson’s history as the enfant terrible of Maryland politics.

In the calculated world of campaigns, Henson, 64, is all swagger and bite in his pinstriped three-piece suits, his dreadlocks falling down his back. More than anything, he is willing to say whatever he deems necessary to win.

“Nazi” and “pseudo-negro” are two of the more indelicate rhetorical rocks he has hurled at political foes over the years. For creating the 2010 robo-call, he was fined $1 million and sentenced to a year in prison, of which all but 60 days was suspended. He also was placed on probation for three years, during which he is banned from campaign consulting.

But Henson’s sentence said nothing about seeking office himself, and having lots of free time, he’s challenging McFadden in the Democratic primary in June. Undaunted by the possibility that his conviction could repel voters, he is employing the raw tactics that often have made him better known than his clients.

“Look at this! Year after year, and what does he do?” Henson asked one afternoon, driving his pickup truck past the boarded-up rowhouses that define portions of East Baltimore and blaming their existence on what he insists is McFadden’s inaction.

“Have you done your job? No!” he said.

The race has captured the attention of Maryland’s political establishment, many of whom Henson has helped win races or have been his target. Besides Ehrlich, Henson’s clients have included a number of prominent Democrats, including former governor Parris Glendening, former lieutenant governor Kathleen Kennedy Townsend, Rep. Elijah Cummings, former congressman Albert Wynn and even McFadden, whose campaign hired him in 2010.

“McFadden has a race on his hands,” said Julian L. Lapides, a former state senator who lost a bid for Baltimore city comptroller to a Henson client. “He should not underestimate Julius Henson. Julius will do whatever it takes to win.”

Still, said Larry Gibson, a University of Maryland law professor, the robo-call case is a formidable obstacle. “I’ve been trying to imagine a more unpardonable sin to the black community than voter suppression,” Gibson said. “If you’re doing an ad for anyone running against Julius Henson, you wouldn’t need to address anything else.”

McFadden’s supporters include state Senate President Thomas V. Mike Miller Jr. (D-Calvert), who has demonstrated little patience for mavericks in his chamber. Miller characterized the race between McFadden and Henson as a choice between an incumbent who is a “family man,” “an educator” and a “moral leader” and a challenger “who was recently incarcerated.”

“It would appear to be a no-brainer,” Miller said.

Henson described Miller as a “jerk” who rewards lawmakers “who are going to kiss his tail. I’m not going to kiss his tail. The only thing Mike Miller is interested in is making himself and his family richer.”

McFadden, Henson said, is “too busy sucking up to Miller and doing what Miller wants. He has served Miller for 20 years. Not the people.”

McFadden, 67, a retired public school principal who is vice chairman of the Senate Budget and Taxation Committee, said in an interview that he’s “not inclined to get down and dirty” and prefers to focus “on what I’ve been able to achieve.”

“I’m nobody’s puppet,” he said, dismissing Henson as a “political operative” with a tenuous grasp of the truth.

“He’s the second coming of Jesus,” McFadden said. He snorted: “If you listen to him.”

Script on a napkin

On Election Day in 2010, as voters were choosing between Martin O’Malley and Ehrlich for governor, Henson was at a McDonald’s in Baltimore with his great-granddaughter. His cellphone rang. Paul Schurick, Ehrlich’s campaign manager, needed Henson to bolster the Republican’s prospects during the early evening hours when they expected a surge of Democratic voters.

Henson said he suggested a robo-call — an automated message delivered by telephone — and scribbled on a napkin a script that Schurick approved. Soon, according to court records, phones were ringing in 112,000 households in Prince George’s County and Baltimore with a message that prosecutors later said was meant to discourage blacks from voting.

“Hello,” the voice said, “I’m calling to let everyone know that Governor O’Malley and President Obama have been successful. Our goals have been met. The polls were correct and we took it back. We’re okay. Relax.”

That Henson, an African American who had mostly worked for Democrats, had joined a Republican campaign was something of a surprise. He said he had supported a number of initiatives during Ehrlich’s term as governor from 2003 to 2007, including his appointment of black judges. Yet during the 2002 governor’s race, when Henson was advising Townsend, he called Ehrlich a “Nazi” whose “atrocious” record in Congress better suited him to “running in Germany in 1942.”

By then, Henson had embraced his reputation as a political hit man, although he was not above expressing regret for his more extreme maneuvers. He showed up at the office of state Sen. Joan Carter Conway after branding her a “pseudo-negro” for endorsing O’Malley for Baltimore mayor in 1999 over a black candidate.

“What is it you want?” Conway recalled asking Henson as he stood at her door and “dropped his head.”

He replied, “I came to apologize,” she said.

Henson says he sees no need to apologize for the 2010 robo-call, saying he intended to encourage voters to go to the polls, not, as a judge wrote, to “dissuade predominantly African-American voters from exercising their constitutional right.”

Ultimately, Henson was convicted of failing to identify the robo-call’s sponsor, an omission he said was the result of Schurick’s order. “I’m a consultant; I did my job,” Henson said. “My job is not to tell him what to do.”

Schurick, who was convicted of seeking to influence voters through fraud, in court described what he had done as a “profound personal failure” and was sentenced to 30 days of home detention and four years of probation.

Prior to his sentencing, Henson described himself as the victim of a “witch hunt” engineered by prominent Democrats who were furious that he had worked for a Republican. He contends that his crime was the equivalent of “jaywalking.”

“Most people,” he said, “think it was a miscarriage of justice.”

Unable to practice as a consultant, he refused to retreat. In East Baltimore, he started attending meetings of the Berea Eastside Neighborhood Association. When the organization held an election for a new president this year, Henson challenged a candidate endorsed by McFadden, who lobbied for his choice in a mass mailing to the members.

Henson won. The senator became his next target.

“I’m supposed to be defeated?” Henson asked. “I’m supposed to be a recluse?

“This is a story about overcoming.”

Mixed opinions

On a Monday night, the neighborhood association assembled for its Christmas party at a recreation center, its members feasting on cakes and pies and singing carols while its president recited the organization’s accomplishments and handed out awards.

“See the love?” Henson said, as he shook hands with an elderly guest.

Julia “Yvette” Eanes-Moore, 57, a microbiologist, said Henson has invigorated the association, opening a computer lab for children at the recreation center and tackling neighborhood traffic issues.

“I see smarts. I see ideas,” she said. Referring to his legal troubles, she said, “Some will hold it against him, but I don’t. People need to forgive.”

Others were not so charitable.

“Who’s going to trust a man like that?” said William Paschall, 70, a retired Navy mechanic. “This guy shouldn’t be nowhere near public office.”

A few minutes later, as “Santa Claus is Comin’ to Town” played from a boombox, McFadden arrived, walking slowly with a cane, his face lit by a beneficent smile.

“How you doing, senator?” someone asked.

“I’m doing wonderful,” McFadden said, taking a piece of sweet potato pie to a table where an elderly woman reached for his hand and a man in sunglasses leaned over to offer a hug.

“McFadden is the man in this district,” Paschall said. “He’s down to earth and on top of a lot of things.”

Henson stood a few feet away, eyes narrowing as he watched the procession.

“They can hug him all they want, but they’re voting for me,” he said, before tapping his inner tactician. He doesn’t need every vote, Henson said. Just one more than the other guy.