If you were wedged inside Car 5306 of the A train from Brooklyn to Manhattan on Tuesday morning, you might have been able to see a political blind date.

There, standing near the door, was Annie Davis, a security guard who works in the lobby of the city’s Department of Health and Mental Hygiene. There, standing next her, was her breakfast companion earlier that morning in her East New York apartment, Mayor Michael R. Bloomberg. And for the better part of the half-hour commute, the two chatted about everything from health care (her insurance plan is not good, she said) to crime (the streets are safer, he said) and the economy (we’re doing our best to help all New Yorkers, he said).

“People need a hand up, not a handout,” Mr. Bloomberg said at one point.

“Exactly,” Ms. Davis concurred.

It was an unusual kind of endorsement interview. Ms. Davis’s union — Service Employees International Union Local 32BJ — is asking candidates for public office to spend part of a day with one of their members to help them relate to these working-class constituents. Last week, Lateef Rivers, a 25-year-old security guard at the Brooklyn Municipal Building, spent part of his shift with the city Comproller, William C. Thompson Jr., a democratic candidate for mayor.  Later they had a Chinese takeout dinner at a desk in Mr. Rivers’ bedroom, since there is no dining table in the apartment he shares with seven roommates.

“Walking a day with a working New Yorker shouldn’t just be a prerequisite for our union’s endorsement, but a requirement for the job,” said Mike Fishman, the president of the union, which endorsed Mr. Bloomberg in 2005, and has 70,000 members.