After a bumpy first two months on the campaign trail, Gov. Andrew M. Cuomo will arrive at the New York State Democratic convention this week with surer political footing.

Hillary Clinton will deliver the keynote address on Wednesday and endorse Mr. Cuomo’s candidacy for a third term. He is widely expected to win the overwhelming support of party leaders to get an automatic spot on the ballot.

And in a fortuitous twist, the person whom Mr. Cuomo most wants to center his campaign against in the primary — President Trump — will be only a few miles away speaking at an immigration forum, allowing the governor a ready-made contrast.

His actual primary opponent, Cynthia Nixon, will be much closer: She plans to attend the Democratic convention (“I won’t be scared out of the room,” she said in a statement), being held at Hofstra University on Long Island, but she’ll be playing on turf largely controlled by party officials appointed by and loyal to Mr. Cuomo.

Ms. Nixon is seeking to garner the 25 percent of the Democratic delegation vote required to win an automatic spot on the primary ballot; her team has played down those expectations.

“I would be surprised if it doesn’t turn out to be a rigged situation,” said Billy Easton, an informal adviser to Ms. Nixon and the executive director of the Alliance for Quality Education, which has endorsed her.

As recently as two weeks ago, Ms. Nixon had seemed to be driving the conversation about the race, on matters big and small, as she cut into Mr. Cuomo’s still-substantial polling lead. She would roll out a position — on everything from a trash incinerator in the town of Romulus to legalizing marijuana — and Mr. Cuomo would seemingly reflexively lurch leftward. Even his allies urged greater restraint.

“Before this campaign is over, he’ll be getting arrested protesting his own administration,” Ms. Nixon joked at a recent roast in Albany.

But the sudden resignation two weeks ago of Eric Schneiderman, the former attorney general who was accused of physically assaulting several women, seems to have served as a reset for Mr. Cuomo, drawing the media spotlight away from Ms. Nixon at a key juncture.

“It certainly changes the fact that there was going to be one central, competitive race,” Mr. Easton said.

The maneuverings over who will replace Mr. Schneiderman have amounted not just to a diversion but an opportunity for exactly the kind of political horse-trading at which Mr. Cuomo, who gained a reputation as a sharp-elbowed operative while managing his father’s campaigns more than three decades ago, has long excelled.

Letitia James, the New York City public advocate, has emerged as the favorite to win the Democratic Party’s backing this week for attorney general, locking up the support of major labor unions and New York’s highest-ranking congressman, Joseph Crowley. She would be the first African-American woman to hold statewide office, and would offer Mr. Cuomo an infusion of diversity after he had flirted for months with the notion of swapping out his lieutenant governor, Kathy Hochul, who is white.

What’s more, Ms. James pointedly snubbed the Working Families Party, which had helped launch her career more than a decade ago, by refusing to compete for or take their ballot line. She had told people Mr. Cuomo’s team wanted her to do so, though Mr. Cuomo has denied this.

Mr. Cuomo has been at war with the minor party since it decided to endorse Ms. Nixon.

“The governor’s fingerprints were all over the moves for attorney general,” said George Arzt, a veteran Democratic strategist in the state. “He’s in much better shape than he was before and he can keep Kathy Hochul,” whom Mr. Arzt described as having been left “twisting” in recent months.

Further complicating matters for Ms. Nixon is that her campaign treasurer, Zephyr Teachout, stepped down to pursue the Democratic nomination for attorney general. A potential primary race sets up the possibility that Mr. Cuomo might campaign alongside Ms. James, whom he endorsed on Tuesday, in black communities.

“That’s what he needs because he knows he’s in trouble,” said L. Joy Williams, a senior adviser to Ms. Nixon and president of the Brooklyn NAACP. “He has a problem and he’s trying to address it.”

Early polls show black voters to be among Mr. Cuomo’s strongest backers. But Ms. Nixon has made breaking into that support a top early priority. She launched her run in Brownsville, Brooklyn, granted her first interview to a historic African-American newspaper and made her first television appearance on “The Wendy Williams Show.”

She also framed legalizing marijuana as a criminal justice issue and called for licenses to sell marijuana to be prioritized for minority communities as “reparations.” She has since backed away from that term under heavy criticism.

Ms. Teachout, who is a member of the Democratic State Central Committee, is seeking the 25 percent support needed to get on the ballot at the convention. “New York has sort of been plagued with a lot of reindeer games and deals and a kind of back-room politics that hasn’t served New York well,” she said.

Leecia R. Eve, a former lieutenant governor candidate in 2006 and former aide to Mr. Cuomo and Mrs. Clinton, has also launched a run for attorney general. Representative Sean Patrick Maloney, who has more than $3 million in his federal campaign committee, also continues to talk to people about running.

If Ms. Nixon, as expected, is not placed on the Democratic ballot by the party, she has already announced plans to petition her way on — a common tactic used in the past by many others, including Mr. Cuomo in 2002, back when he was running against the party’s preferred choice.

Then, Mr. Cuomo said, petitioning would allow him to take his campaign “to the people” and to run against “a culture of dysfunction in Albany” — lines that could be revived verbatim by Ms. Nixon in 2018.

Unlike Mr. Cuomo then, Ms. Nixon will be roaming the convention halls herself.

“We don’t believe that we’re going to beat him in this space,” Ms. Williams said. “But we are going to talk and engage directly with state committee members.”

Follow Shane Goldmacher on Twitter: @ShaneGoldmacher.

Jesse McKinley contributed reporting.