By a two-to-one margin, the faculty of Princeton University adopted on Monday a nonbinding proposal to cap the number of A-range grades given to its undergraduates.

The unprecedented proposal, first released three weeks ago, calls for the proportion of A-plus, A and A-minus grades for undergraduate courses to be held under 35 percent in each department.

While the initial proposal called for a hard cap, the move that passed at Monday’s faculty meeting was amended to call for an “expectation” of 35 percent A’s rather than the originally-proposed “limit.”

It marks the first major step by a top-tier university to curb grade inflation, and Princeton will begin this fall to phase in the plan over three years.

“Thirty-five percent A’s will set us apart from the pack in a way that identifies Princeton as a real leader in tackling this problem,” Princeton Dean of the College Nancy W. Malkiel wrote in a cover letter accompanying the proposal.

Princeton’s move comes as Harvard is in the midst of curricular review that is not considering grade inflation, and University President Lawrence H. Summers said in an interview last week that the curricular review is a higher priority for the College than combating grade inflation.

“I am very troubled by the fact that grade inflation is returning, but I think the priority this year is thinking about curriculum reform,” he said.

Princeton’s formal consideration of the issue began in a faculty committee which issued a set of recommendations released to Princeton faculty on April 8.

Malkiel presented the proposal at Princeton’s Monday faculty meeting, and after a 90-minute debate, they approved the revised measure by a vote of 156-84.

Malkiel declined to comment yesterday, citing her policy of not speaking to student newspapers other than the Daily Princetonian.

But she told the Daily Princetonian Monday that the plan is not intended to override professors’ prerogatives.

“These proposals do not try to tell faculty how to teach,” Malkiel said. “No faculty member should fail to give an A to a student who deserves it.”

The measure comes in response to well-documented grade inflation, at Princeton, Harvard and other elite universities.

Last year, both Princeton and Harvard awarded about 47 percent A grades. And a study conducted by Malkiel found that 11 top schools—Stanford University, MIT, the University of Chicago and the Ivy League universities—have given 44 to 55 percent A-range grades in recent years.

Summers declined to comment through a spokesperson yesterday.