Maryland Gov. Larry Hogan, left, and Democratic gubernatorial nominee Ben Jealous. (Pete Marovich for The Post and AP)

Maryland Gov. Larry Hogan (R) has a considerable lead over Democratic challenger Ben Jealous and is supported by slightly more than half of likely voters, according to a poll released Tuesday by Gonzales Research and Media Services.

Hogan, who has governed as a moderate and repeatedly distanced himself from Republicans in Washington, leads Jealous 52 percent to 36 percent with 11 percent of likely voters undecided. The margin is similar to Hogan’s 18-point lead in a June poll by the same firm.

The poll raises questions about whether Jealous, who Hogan and the GOP have repeatedly attacked as too “extreme” for Maryland, can expand his appeal beyond the progressive base that elected him in a six-way primary. It found that while Hogan remains widely popular in a state where Democrats outnumber Republicans 2 to 1, the unfavorability ratings for Jealous, a former NAACP president, have increased over the past two months.

While 19 percent of surveyed voters held a negative view of Hogan, 33 percent said they felt that way about Jealous — a 19-point spike since the last Gonzales survey. The increase is primarily among Republicans and independent voters and is particularly pronounced among Republicans, whose disapproval of Jealous rocketed from 21 percent to 71 percent.

Since the day after the primary, Hogan and his backers have hammered Jealous’s proposals for universal health care and increasing taxes on the richest Marylanders to pay for expanding government programs. The Republican Governors Association has targeted him with more than $1 million in attack ads, which have gone unanswered on the airwaves by Jealous and his Democratic allies.

Last week, asked about Republican attempts to label him a socialist, Jealous dismissed the idea with an obscenity.

The Gonzales poll, conducted mostly before that incident, offers some hope for Jealous to close the likability gap: Roughly 1 in 5 voters said they didn’t have an opinion about him, and 15 percent did not recognize his name.

His favorability rating ticked up slightly to 31 percent, an increase that was within the poll’s margin of error. And three-fourths of the undecided voters in the race are registered Democrats, suggesting that Jealous could still gain significant ground.

But with Hogan slightly above 50 percent — and his job-approval ratings above 70 percent — Jealous will have to find a way to damage the governor’s credibility or make good on his pledge to dramatically drive up Democratic turnout to close the gap.

Jealous “will need to work out a way to infuse some pizazz into his campaign within the next month, in order to give himself at least a modicum of momentum for the fall campaign,” pollster Patrick Gonzales said. “The burden is always on the Republican in deep-blue Maryland, but the Democrat still does need some positive thrust.”

At a briefing with reporters last week, aides to Jealous outlined a plan to beat Hogan by strongly boosting turnout among Democratic voters disgusted with President Trump.

The Gonzales poll confirms that Trump is deeply unpopular in Maryland — 58 percent disapprove of the job he’s doing — but suggests an anti-Trump wave would not necessarily lead to a Jealous victory.

Among voters who do not already prefer Jealous as their candidate, 13 percent said they would consider voting for him “as a way to express disapproval of Donald Trump.” Seventy-seven percent said they would not consider supporting him as a protest vote against the president.

“Trump’s negatives might ultimately help him, but only a tad,” Gonzales said.

Hogan has an enormous financial advantage in the race, and both he and Jealous are supported by outside groups willing to spend money on their behalf.

Jealous received a potential boost Monday with the endorsement of a new political group that is focused on improving the economic fortunes of black Americans and has raised $3.5 million over the past two months.

The Black Economic Alliance said it plans to invest in “competitive contests” that emphasize improved economic conditions for black voters and in which African American turnout is crucial to victory.

Before the poll was publicly released, the Jealous campaign obtained a copy and questioned its credibility, noting in a statement that previous surveys by Gonzales did not accurately predict Jealous’s strong primary victory. The statement said the Jealous campaign had conducted internal polling that showed a more competitive race.

Hogan campaign spokesman Scott Sloofman said the campaign sees the poll as validating Hogan’s tenure as governor, noting its finding that, by wide margins, Marylanders from all political backgrounds think the state is headed in the right direction.

While Hogan is leading the contest overall, Jealous has stronger support among Democrats and African Americans and among voters in the Washington metro region.

Hogan is dominating the race in rural areas, among white voters and in the Baltimore area.

The poll of a random sample of 831 likely voters was conducted Aug. 1-8 on landline and cellular phones and has a margin of error of 3.5 percentage points.