The decision by District leaders to pursue a candidate for school superintendent who will not commit to serving longer than a year has sparked sharp debate among the city's education activists and public officials.

Supporters of hiring Carl A. Cohn, including Mayor Anthony A. Williams (D), contend that he is the best person available for the job and that bringing him in for a year -- and possibly persuading him to stay longer -- is better than offering the post to someone else.

But others argue that the school system needs continuity and that the city should keep looking for a top-quality schools chief who is willing to remain in the job for the long term.

Several education analysts praised Cohn, who served as superintendent in Long Beach, Calif., for a decade. But they said that hiring him to run the District's 64,200-student system for only a year could be risky.

In the best scenario, they said, Cohn could lay the groundwork for improvements in a system with test scores that are among the lowest in the country and then pass the baton to a top deputy who would finish implementing his programs. But they also expressed concern that Cohn's efforts to bring changes could be stalled by a bureaucracy that viewed him as a short-timer and that his agenda might not survive his departure.

"It would be very risky," said Bruce Fuller, a professor of education and public policy at the University of California at Berkeley and an admirer of Cohn. "One reason Carl Cohn had such a dramatically positive impact in Long Beach was because of his staying power. People knew Carl Cohn would be at the table a long time to implement his vision. . . . If people thought Carl would disappear in a year, my fear is they would just wait him out for a year and implementation would just go up in smoke."

The District has had four superintendents in the past eight years, in addition to two interim chiefs who have served in the past eight months. The result, some school activists complain, has been that there has been no consistency in approach and that changes initiated by one leader are quickly discarded by another.

Cohn himself acknowledged in an interview last week that a one-year contract is not the best option.

"I'm not going to say a one-year appointment is an ideal thing for a school system that's down," he said. "But I think there's no question that a lot can be accomplished."

He said that within a year he could bring in a team of high-caliber administrators and build a system of rigorous academic standards, teacher training and effective assessment. He said those "pillars" would form a foundation for his successor, and he suggested that that person could be selected from the group of administrators he hires. He also said that those he hires could stay in their jobs after he leaves and offer continuity.

Cohn was one of four finalists considered by a panel of seven city and school officials to replace Paul L. Vance, who resigned as superintendent in November. Williams, a member of that panel, initially wanted to hire Rudolph F. Crew, the former chancellor of New York City schools, but last month he accepted the school superintendent's job in Miami-Dade County.

Despite Cohn's comments last week that he would not commit to staying in the District longer than a year, the panel forwarded his name to the school board and the board voted unanimously to begin negotiations with him.

Before announcing that he did not want to serve more than a year, Cohn had said that D.C. officials -- who were then debating changes in the school oversight structure -- needed to keep the same structure in place for at least four years. He said it would be hard for him to attract staff and see changes through without that stability.

In the more recent interview, Cohn acknowledged that "there is some degree of inconsistency" between those comments and his desire for a one-year contract. But "on a personal and professional level," he said, "I'm not ready to make a longer commitment." He said that his wife has a job in Southern California and that one of his children lives in Long Beach and another is going to college in Hawaii.

However, Cohn, who works as a schools consultant and professor at the University of Southern California, said he might be willing to talk about extending his tenure "down the road."

At this point, Cohn has not committed even to a year-long contract. He has said that city and congressional leaders first need to hold a "summit" and sign a written agreement to address a number of issues that are impediments to school improvement.

The changes he wants include making the school system's chief financial officer report to the superintendent instead of to the city's chief financial officer; aligning the school system's fiscal year with the school calendar; and eliminating the requirement that the D.C. Council approve school contracts that are multi-year or greater than $1 million. He said that D.C. schools should not be subjected to requirements more burdensome than those in suburban school systems, such as Montgomery County.

Williams has committed to holding the summit Cohn wants and to luring him to the District.

"I believe it's better for our system to have him come in here even if it's only for a year and begin putting in place the building blocks to rebuild the system," Williams said at a news conference last week.

Several members of the school board, which ultimately must approve of any hiring, said they had concerns about a short tenure but were impressed with Cohn. They would not say what he could accomplish in a year, saying that would be the subject of negotiations.

D.C. Council Chairman Linda W. Cropp (D), a member of the panel that recommended Cohn, would not say whether she thought that hiring another candidate for a longer term would be better than hiring Cohn for a year. She said she thought that Cohn would be good for the city and hoped that he would agree to stay longer.

"I'm still hopeful . . . that it will be for a longer period of time," Cropp said.

Leaders of the city's two best-known school activist groups -- the Congress of PTAs and Parents United for the D.C. Public Schools -- have said that a year would not be enough time for a superintendent to make improvements and that such an appointment could ultimately set the school system back.

Other school activists are expressing similar concerns. "It's the most ridiculous thing I've ever heard," William P. Wilson, a Ward 7 schools activist, said of a year-long superintendency. "What can you do in a year? You can't even get acclimated. . . . Let's have some kind of continuity."

Council member Adrian M. Fenty (D-Ward 4) said he does not understand why city leaders are pursuing a candidate who does not want to work in the District more than a year. He said the city is "acting desperate."

"I think they're settling on a length of work that's clearly not what they're looking for," Fenty said. "If we're just walking around acting like we'll take whoever will come under whatever conditions, we'll get what we pay for and have someone who's not committed to this system."

Kelvin J. Robinson, the mayor's chief of staff, said he thought that the city could create the right conditions to encourage Cohn to stay.

"The decision was to pursue someone who could do the kind of rapid change that we're looking for," he said. "Who's to say that he won't be that long-term person?"