A Yale union’s support of two Democratic aldermanic candidates brought mixed results to the New Haven Democratic primaries last week.

In Ward 28, Claudette Robinson-Thorpe — the aldermanic candidate backed by Local 34, which represents 3,400 Yale clerical and technical workers — was victorious last Tuesday, edging over incumbent Ward 28 Alderman Mordechai Sandman by 19 votes. Sandman said the union’s efforts in his neighborhood — including signing up dozens of constituents to vote for his opponent — led to his defeat.

“Evidently, it worked,” Sandman said Sunday night.

Some aldermen, such as Sandman, said union campaigning will likely be used in future aldermanic campaigns because of its effectiveness in Ward 28.

But Local 34’s efforts were not universally successful. In Ward 24, Local 34 officials sent to constituents at least one letter backing incumbent Ward 24 Alderwoman Elizabeth McCormack. Yet she lost last week to Marcus Paca, whom New Haven Mayor John DeStefano Jr. supports.

Reached at home Sunday night, McCormack said she appreciated the union’s efforts. She said she plans to continue teaching communication classes at Southern Connecticut State University and Gateway Community College.

“I have another life,” she said. “I lost. I’m disappointed, but I’m not devastated.”

Sandman, on the other hand, said he plans to remain involved in the community by participating in local block watches and working with the ward’s management team. He added that he is unsure whether he will run for aldermen in the future.

“I’m still, you know, digesting what has happened. And I’m making a few decisions with my family at this point of time,” he said. “But just because I lost doesn’t mean I’ve left the neighborhood.”

Local 34 President Laura Smith said last week that the union endorsed the progressive aldermanic candidates “who support issues of working families and organizing rights.” The union endorsed Robinson-Thorpe because, Smith said at the time, Sandman did not support a piece of legislation two years ago designed to chastise a linen supply company for its alleged poor working conditions. But Sandman responded that he could not, in good conscience, sign legislation to reprimand a local business without first meeting with representatives from the company.

Sandman said the union successfully registered young adult residents in his neighborhood — a group that generally does not vote in elections — and rallied them behind endorsed candidates. The strategy worked: On the last day of voter registration, Sandman said, the union signed up 150 residents in his ward.

It remains to be seen what will happen in Ward 10, where Local 34 endorsed incumbent Green Party candidate Allan Brison over Democratic candidate Justin Elicker FES ’10 SOM ’10. The general election will occur in November.