During a staff meeting in November, after learning that a recording of an earlier meeting had been leaked to a reporter from The New York Times, Mr. D’Vorkin said anyone involved with the act was “morally bankrupt,” according to several people in attendance.

“Our recent change of newsroom leadership provided our managers a brief opportunity to restore some trust. They chose not to try,” Doug Smith, a senior writer who has worked at The Times for nearly 50 years, wrote in a post in support of the union. “For the first time in my nearly five decades at The Times, I, along with my colleagues, have been publicly scolded by my publisher and by my editor.”

In an emailed statement, a Tronc spokeswoman said, “The Company urges every individual in the LA Times newsroom to get out and vote. We believe that by working together, rather than through a third party, we can build on the LA Times heritage and trust with readers. We remain committed to providing a productive and safe working environment for all employees, and will continue to act with the best interest of all of our employees in mind.”

As newsroom employees prepared for the election, the union organizing committee has tried to combat Tronc’s anti-union push by reporting on The Times and the compensation and perks its leaders receive. In November, it published a report on its website about Tronc executives, including Michael W. Ferro Jr., the company’s chairman. The report detailed what the committee described as “outsize compensation” for company executives, as well as Mr. Ferro’s use of a private jet that Tronc had paid to sublease from Merrick Ventures — a company led by Mr. Ferro.

On Dec. 22, the Friday before Christmas, Tronc disclosed in a filing with the Securities and Exchange Commission that it had agreed to pay Merrick Ventures $5 million annually on a rolling, three-year basis “to provide certain management expertise and technical services.” The news — even as some employees say they have not received raises in years — rankled many in the newsroom and helped bolster the unionization effort. Tronc had been pushing for the election to be held in mid-December, before it disclosed the agreement, according to two people familiar with the process. (The company said the contract was a replacement for the private arrangement of the aircraft sublease.)

Workers at many of the country’s prominent news publications, including The Washington Post, The New York Times and The Wall Street Journal, are represented by unions. There has also been a recent push for organization at digital news outlets; employees at several such companies, including HuffPost and Vice Media, are now union members.