The next mayor’s race is more than three years away, but the state Democratic convention is a little more than just three months from now. That fact might explain why a delegate battle between Boston mayor Tom Menino and State Representative Martin Walsh of Dorchester, a potential mayoral rival, became so hotly contested last week.

It’s a bit mysterious from afar, and insiders aren’t talking. But Menino had much to gain when his son-in-law, Billie Fenton, organized the so-called Patriots slate to go up against Walsh’s in Ward 13’s Democratic caucus last Wednesday. In the long run, a caucus victory by Menino’s son-in-law could mean defeat for Walsh, a popular politician touted as a future candidate for Boston mayor; in the short-run, a win would mean more delegates for Menino to control at the May 31–June 1 state Democratic convention — adding to his reputation as a party power broker.

On hand at the St. Mary’s Women and Infants Center in Dorchester were more than 100 participants. Overwhelmed by the large crowd, Walsh postponed the caucus.

"I’m trying to reschedule the caucus and put it in an area that meets all the requirements and is handicapped-accessible," says Walsh.

As for Menino’s part in the affair, his press secretary, Carole Brennan, declined to comment. "The mayor’s not directly involved in any of the ward races," she said. A Menino supporter, noting that Fenton and Walsh have been at odds since Walsh backed former state representative Jim Brett instead of Menino in 1993, cautioned against making too much of the delegate dispute. "Marty’s impetuous sometimes," says the Menino supporter. "He wants to be a player, and sometimes he moves in all directions at once."

One thing is certain. When the caucus eventually does take place, it will likely garner significant attention.