When Montgomery County Executive Douglas M. Duncan travels to Baltimore today to announce that he's running for governor, two of the city's former mayors will be standing beside him.

State Comptroller William Donald Schaefer (D) and Kurt L. Schmoke (D), who have had tense relations over the years, will join together to endorse Duncan, who is running against Baltimore's current mayor, Martin O'Malley, in the Democratic primary next year.

"This is a complete, total pro-Doug Duncan stance," said Schmoke, the dean of Howard University's law school who was mayor from 1987 to 1999. "I think he is not only a fine person, but he will make an outstanding governor and is a great public servant."

Schaefer, who was mayor from 1971 to 1986 before serving two terms as governor, and Schmoke have been working for months to boost Duncan in a city where he remains largely unknown.

Schmoke said he and Duncan have been friends for years. Schaefer is a frequent O'Malley critic who plans to support Duncan in the primary but has not ruled out backing Gov. Robert L. Ehrlich Jr. (R) in the general election.

Over the summer, Schmoke introduced several dozen party activists to Duncan at an event in Baltimore. "We will continue to work up until the Election Day," he said.

Much of Schaefer's political network -- including his big-money contributors and longtime supporters -- are also backing Duncan.

It remains to be seen whether the past mayors can deliver a significant number of votes. Schaefer's disparaging comments about immigrants and AIDS patients last year alienated some Democrats, as has his alliance with Ehrlich.

As mayor, Schmoke gave crucial early backing to former governor Parris N. Glendening (D) in 1994. Four years later, however, Schmoke endorsed Glendening's primary opponent, Eileen M. Rehrmann, who took just 13 percent of the vote statewide.