DETROIT — The election of Shawn Fain as the UAW‘s fifth president in five years could upend what are already expected to be difficult contract negotiations between the union and Detroit 3 automakers later this year.

But his razor-thin margin of victory over incumbent Ray Curry — Fain won by fewer than 500 votes and received the support of less than 7 percent of the UAW’s membership — could make it tough to rally a disgruntled membership eager to move beyond the union’s troubled past.

“No one can declare they have a mandate,” said Marick Masters, a business professor at Wayne State University in Detroit who specializes in labor issues. “The membership is obviously divided. I think the No. 1 challenge facing Fain is to unite the membership behind a bargaining strategy.”

Fain, who was sworn in on Sunday, will have to hit the ground running. Union leaders from around the country will gather this week for a special bargaining convention, where they’ll vote on resolutions and priorities to guide their strategy this fall.

Fain, 54, has promised a shakeup in the way the UAW will engage with Ford Motor Co., General Motors and Stellantis, declaring late last year that the “cozy labor-management relationship is on its way to the dustbin of history.” As his victory became clear earlier this month, he proclaimed “change had come” to the union.

But such an aggressive stance from a newly elected leader who has never engaged at the highest levels of contract negotiations could complicate what will be delicate talks over job investments and benefit increases.

“The rhetoric has been high and the tone that the leadership has set is more militant and antagonistic than it has been in the past,” Masters said. “I think that we’re entering into somewhat uncertain waters with new leadership that will have a challenge in getting the membership behind it and also in developing a coherent strategy.”

Regardless of whether Fain will be more congenial as the president than as a candidate, the Detroit 3 should prepare for a new reality, said Art Wheaton, a labor expert at Cornell University.

“Should Ford, GM and Stellantis be nervous? Absolutely,” Wheaton said. “I don’t think they’re going into these negotiations from the UAW side looking to get a quick, easy settlement. I think they’re going in to make these negotiations as tough as they can to try and achieve a maximum amount of gains, even at the expense of long-term relationships.”

In that regard, at least, Fain and Curry are similar. Both have expressed a desire to secure job commitments from the Detroit 3, especially related to new EV investments and battery joint ventures. They also expect to protect health care plans and restore lost benefits like cost of living adjustments, among other gains.

Fain, a member of the UAW international staff in the Stellantis department, has some experience in negotiations, being part of bargaining teams with the Detroit 3 in 2009 and 2011.

But as president, Wheaton says he’s likely to discover making good on his campaign promises could be easier said than done.

“That’s the nature of collective bargaining, you never get everything you want,” Wheaton said. “I think it will be somewhat of a rude awakening for those who elected him when he will most likely be unable to deliver on all of his promises.”

Fain’s victory is part of a larger upheaval on the union’s 14-person International Executive Board. Candidates who ran on Fain’s UAW Members United reform caucus won each of the seven races they contested, while another independent candidate won an eighth seat.

Still, Fain’s victory was not without controversy.

He came in second during the first round of voting, but advanced with Curry to the runoff after none of the five candidates received a majority of votes.

The runoff results were delayed by nearly two weeks after the court-appointed monitor overseeing the count had to pause to verify nearly 1,600 challenged ballots. As the final tally commenced, Curry’s team filed a protest with the monitor, arguing numerous issues “call the election into question and require immediate investigation.” The monitor later said Curry’s team demanded a halt to the vote-count and that another runoff take place.

Curry’s team argued that “tens of thousands of ballots” were returned to the union as undeliverable and questioned whether the monitor’s office made “all reasonable efforts” to ensure those members could vote.

They also called into question the validity of Daniel Vicente’s victory as director of Region 9, which represents workers in New York, New Jersey and Pennsylvania. Curry argued that Vicente was not able to run because he had not paid the dues necessary to be a UAW member in good standing until after the original November vote.

Curry also said campaign rules were not consistently enforced and that campaign donations to his opponent came from employers with whom the union has a bargaining relationship, which would be against the rules.

The monitor dismissed Curry’s calls for a new election, although it’s unclear if he’ll take additional steps to challenge the results.

In the meantime, Fain will have to build out his staff within a UAW bureaucracy he criticized as a candidate. According to a transition memo first reported by the Detroit Free Press, he plans big shakeups within the union’s staff.

Masters said whom Fain surrounds himself with, and whom he places on bargaining committees this fall with the automakers, will be key.

“It’s going to be very interesting,” he said. “I would watch very carefully who he puts in key positions because that will tell you an awful lot.”