As the aldermanic candidates in Ward 9, a mecca of Yale graduate students and faculty, head into Tuesday’s primary, the words between them have grown increasingly charged.

In an election season that has been defined by labor tensions, Ward 9 is no exception. In an explicit push by both Yale and city unions to beef up resistance to Mayor John DeStefano Jr.’s fiscal policies on the Board of Aldermen, an unprecedented number of union-affiliated candidates are running in races throughout New Haven this year. Jessica Holmes, a former organizer with Yale’s Local 34 who lost to Ward 9 Alderman Matt Smith ’98 in a nail-biter of a special election last November, is giving Smith another vigorous challenge this year with the financial backing and public endorsements of labor unions. In some quarters of the city’s political scene, that effort is considered a brazen political power grab, while in others it is an overdue chance to lend a more powerful voice to the city’s working class. While Smith, a graphic designer and lifelong East Rock resident, said he is no enemy of organized labor and has relatives in unions, he believes the extent to which Holmes has benefited from union support would compromise her ability to fight for the interests of Ward 9 over union objectives.

Indeed, Holmes’ campaign finance report reveals that a quarter of her campaign cash comes directly from unions, with the Central Labor Council, AFSCME Council 4 and UNITE HERE Local 26 each contributing the maximum $375. Despite his lack of union support, Smith out-fundraised Holmes by $220, according to the latest finance reports from both campaigns.

But the conspiracy theories that abound claiming unions are attempting a hostile takeover of city government are simply the result of “fear-mongering,” Holmes said. Both city and Yale unions, after all, are comprised of working people in New Haven, she said.

“Union support comes from working people’s dues, from secretaries, from lab technicians,” she said. “It’s very different from [the contributions of] some corporate interest — everyone knows that the interests of working people have been underrepresented in government for too long.”

Furthermore, the organizational support unions provide makes it easier for people without connections or personal wealth to break into politics, Holmes said, which enhances democracy by bringing “fresh blood” into the system. In August, Yale’s unions endorsed 15 aldermanic candidates, including Holmes, and last week, AFSCME Council 4 endorsed Holmes along with candidates in 13 other wards.

In a criticism unrelated to Holmes’ union ties, Smith pointed out that many of the contributions Holmes’ campaign has received come from employees of Achievement First, the charter school group where her partner, Katie Poynter, works. In general, he said, his campaign has greater support from within Ward 9.

Both Holmes and Smith agreed that the race is more complicated than a contest between a “labor union woman and a City Hall man,” as Holmes put it, but their approaches to the contentious labor issues of the past year reveal a significant ideological split between the two.

Holmes criticized Smith for not signing an aldermanic letter asking DeStefano to rescind the layoffs of 16 police officers in a round of budget cuts in February, suggesting it fit in a pattern of Smith’s reluctance to hold decisions made at City Hall up to adequate scrutiny. She would also have been more forceful than Smith, she said, in opposing DeStefano’s plan to privatize the city’s school custodians, a matter that is still being negotiated in a state arbitration process.

Holmes’ wariness of restructuring city employees’ health benefits and pensions, which have risen from 12 to 22 percent of city expenditures in the past decade, is troubling, Smith said.

“The way our pensions are structured, we can’t fund them in a sustainable way, and when people don’t recognize that it gives me a little pause,” Smith said. “We still want to be fair to our workers, but some of the plans are very generous and now is the time we can take a look at them.”

Smith combated Holmes’ suggestion that he has failed to establish himself as independent from City Hall and, in his nine months as alderman, said he has made the community’s concerns, not the mayor’s, his top priority.

In particular, when the city struggled to remove snow from severe January storms that left many streets impassable for weeks, Smith said he was the first alderman to criticize a “lack of leadership” in City Hall, and that he was a vocal critic of the mayor’s when DeStefano unveiled a plan last year to sell the city’s parking meter revenue for a short-term budget boost.

Smith has also worked with businesses on State Street to create a program that makes it easier for them to recycle, helped bring traffic-calming tools such as speed bumps to the ward and organized residents around an effort to rebuild the East Rock Global Magnet School as a competitive alternative to the highly-ranked Worthington Hooker School.

“Having lived here all my life, I’ve had the opportunity to develop strong relationships with people who have chosen to make this community their home,” Smith said. “I am committed to this neighborhood.”

Holmes praised Smith’s performance in “constituent services” such as these, but she said he has not delivered on the potential of a Ward 9 alderman to make an impact on citywide issues.

Because the contest in November in which Smith narrowly defeated Holmes was a special election to fill the departing Roland Lemar’s seat, Holmes and Smith did not compete in a Democratic primary. Instead, the Ward 9 Democratic Committee endorsed Smith, forcing Holmes to run as an independent.

While Tuesday’s primary will decide the Democratic nominee for the seat, both candidates have registered as independents and said they will run in the Nov. 8 general election if defeated in the primary.

Democrats registered to vote in Ward 9 can cast their primary ballots Tuesday at Wilbur Cross High School at 181 Mitchell Drive.