In the ongoing battle for preeminence between the Harvard and Yale law schools, the departure of Harvard’s high-profile dean could be a game-changer.

With a recent string of departures from Yale Law’s faculty, some in legal academia had begun to voice concerns about whether the school could maintain its preeminence as the nation’s top law school, especially as Harvard Law reinvented itself under the deanship of Elena Kagan. But with Kagan set to depart from Harvard to become the nation’s next solicitor general, can Harvard Law School maintain its momentum?

“Kagan was the ideal dean,” said Harvard law professor William Rubinstein ’82. “It will be tough to follow in [her] footsteps because she’s just been so successful in so many areas.”

Appointed as dean just two years after she arrived in Cambridge, Kagan sought to shake off long-standing stereotypes about the school’s low quality of life. Six Harvard law professors interviewed by the News said Kagan’s innovations — which ranged from small changes such as free coffee and bagels for students to much more ambitious projects such as curricular reform and the adoption of a modified pass-fail grading scheme — went far in making the school more student-friendly.

Harvard law professor and high-profile lawyer Alan Dershowitz LAW ’62 said Kagan’s humanization of the school was the most important part of her legacy, an opinion fellow professor Jeannie Suk ’95 shared.

“Between the era when I was a student at Harvard Law School in 1999-2002 and when I returned as a professor in 2006, morale had improved tremendously,” said Suk in an e-mail. “This happened on Dean Kagan’s watch.”

In addition to improving student life at the school, Kagan oversaw a hugely successful capital campaign, raising over $300 million during her 5 1/2 years as dean. Kagan also pushed to expand the school’s physical size, with the 250,000-square-foot Northwest Corner complex slated to open in 2011.

Perhaps more controversially, Kagan engaged in the “poaching,” or lateral hiring, of tenured professors from other law schools. Since Kagan became dean in 2003, Harvard Law School has landed several major appointments, including the hiring of Cass Sunstein, the nation’s most-cited legal scholar, from the University of Chicago Law School and cyber law expert Lawrence Lessig LAW ’89, who rejoined Harvard’s faculty after nine years at Stanford Law School.

Kagan declined to be interviewed for this article.

Given Kagan’s successful tenure as dean, professors were not shocked when President-elect Barack Obama — a former associate of Kagan’s when both served on the faculty of the University of Chicago Law School in the early and mid-1990s — nominated her to become his administration’s solicitor general.

“She was so good at what she did that people accepted that she wasn’t going to be here forever, that another opportunity would come along,” said Harvard law professor Richard Fallon ’75 LAW ’80, who added that Kagan left the school with a great deal of forward momentum.

But within days of Kagan’s appointment, Sunstein — who was hired only last year — also announced he was leaving Harvard Law School to head the federal Office of Information and Regulatory Affairs.

Professors dismissed any notion Sunstein’s departure is the start of a faculty exodus, citing Harvard Law School’s tradition of public service.

“There’ll undoubtedly be a number of people who will head off to Washington, but I look forward to the return of virtually all, if not absolutely all, of them,” said Fallon.

Although professors generally expressed confidence that Kagan’s successor will be able to build upon her achievements, they also stressed that great care will be needed during the search process.

“This is going to be [Harvard President] Drew Faust’s first major appointment, and I hope she’ll make a wise one,” said Dershowitz.

Regardless of who will succeed Kagan, professors agreed that Kagan has left Harvard Law School much stronger on all fronts. But many avoided the question of whether the school had surpassed Yale Law School.

“There is no doubt today that Harvard is the greatest large law school in the United States, and there is no doubt today that Yale is the greatest small law school,” said Fallon. “Comparisons between the large and the small are like comparisons between apples and oranges.”

One professor, however, stated his opinion more openly.

“Well, obviously I’m biased, but I think that HLS has already overtaken YLS in terms of overall quality,” said Harvard law professor Mark Tushnet GRD ’71 LAW ’71 in an e-mail.

Harvard Law School announced Thursday that professor Howell Jackson will serve as acting dean, pending Senate confirmation of Kagan’s nomination.