The race to lead America’s third-largest city centers around public safety and education, but could also add to the trend of Asian-American and — to a lesser extent — Hispanic voters leaning toward a relatively conservative approach to governance. 

According to a poll from the Illinois-based firm Victory Research, a former Chicago public schools CEO, Paul Vallas, leads the Cook County commissioner, Brandon Johnson, by 44.9 percent to 39.1 percent. Undecided voters make up 16 percent of the total. 

Chicago elects its mayors with a two-round voting system where the top two vote-getters move on to the second round. In the first round of voting, Mr. Vallas won 32.9 percent of the vote and Mr. Johnson won 21.6 percent. 

The two most powerful unions in the city are mobilizing members for their chosen candidates, with the police backing Mr. Vallas and the teachers supporting Mr. Johnson. Before running for elected office, Mr. Johnson was a paid organizer with the Chicago Teachers Union. 

The battle for the mayoralty comes down to one critical voting bloc: Hispanics. The Victory Research poll showed the two candidates in a virtual tie among the group, with Mr. Vallas garnering 39.9 percent of support and Mr. Johnson with 38.3 percent. 

Mr. Vallas performed well with Hispanic voters last month. In the first round of voting, Congressman Chuy Garcia — who is Hispanic — won the ethnic group, but Mr. Vallas was close behind him, even winning a few of the city’s majority-Hispanic wards. 

Hispanics are the third-largest ethnic group in Chicago, with 28.6 percent of the population. White residents account for more than 47 percent of the total, while Black voters make up 29.2 percent. 

Chicago’s Asian-American voters broke decisively for Mr. Vallas in the first round of voting. In a landslide victory among the group, he garnered 58 percent of their votes in a nine-candidate field. Asian-Americans are only 7 percent of the city’s total population, but by winning that group by such a large margin, Mr. Vallas has a better chance of getting over the finish line. 

In 2022, large cities like New York saw Asians move further toward the Republicans than any other ethnic group. In 2020, President Biden won Brooklyn’s Chinatown district with more than 70 percent of the vote, but Congressman Lee Zeldin went on to win the neighborhood just two years later in his quest to become New York’s governor. 

The racial divides in Chicago could not be more stark, according to this poll. In the city’s white neighborhoods on the northwest and southwest sides, Mr. Vallas leads by about 40 points. Mr. Johnson’s support mirrors his competitor’s — taking the Black vote by nearly 35 points. With Hispanics evenly split between the two, the Latino voters on the west side could prove to be the decisive factor.

At a forum on Saturday, the two men traded barbs over their political pasts. Mr. Johnson was accused of not supporting law enforcement amid skyrocketing crime rates in the city. In 2020, he sponsored a resolution that called for cutting police budgets and called defunding the police a “political goal.”

Mr. Vallas was accused of being in bed with Republicans. In a 2009 interview, Mr. Vallas said he was “more of a Republican than a Democrat.” He has also been criticized for campaigning alongside the Chicago police union, which recently hosted Governor DeSantis at a fundraising event. 

The head of Victory Research, Rod McCulloch, told the Sun that the police union endorsement helped get Mr. Vallas to the second round of voting and could help him become the city’s mayor. “There’s no question where his support comes from,” Mr. McCulloch said. “It comes from the northwest part of the city and the southwest part of the city where a lot of first responders live.”

Mr. McCulloch said that Mr. Johnson’s best chance of taking a poll lead is hammering Mr. Vallas for his associations with Republicans via the police union. “It depends whether or not they can make the ‘Paul Vallas is a Republican’ thing stick,” Mr. McCulloch said in a phone interview. 

According to FiveThirtyEight, which analyzes the trustworthiness of certain pollsters, Victory Research has correctly predicted 91 percent of the elections it has surveyed.