The U.S. Justice Department has backed key arguments made in an antitrust suit against 16 private colleges and universities.

In a brief filed Thursday, the department did not seek to join the suit but said it was stating “the interest of the United States.” Specifically, the brief is an answer to a motion by the colleges to dismiss the case.

The colleges accused of violating antitrust law defend their action by citing the “568 Exemption” for colleges that admit all their students in a need-blind way. But the Justice Department says that “an agreement between schools that admit all students on a need-blind basis and schools that do not is beyond the scope of the 568 Exemption. Thus, to the extent that at least some of the defendants do not admit all students on a need-blind basis, the 568 Exemption would not apply here.”

The targets of the suit are Brown, Columbia, Cornell, Duke, Emory, Georgetown, Northwestern, Rice, Vanderbilt and Yale Universities; the California Institute of Technology; Dartmouth College; the Massachusetts Institute of Technology; and the Universities of Chicago, Notre Dame and Pennsylvania.

All these colleges say they are need blind.

But the suit says, “At least nine defendants for many years have favored wealthy applicants in the admissions process. These nine defendants have thus made admissions decisions with regard to the financial circumstances of students and their families, thereby disfavoring students who need financial aid.”

The nine are Columbia, Dartmouth, Duke, Georgetown, MIT, Northwestern, Notre Dame, Penn and Vanderbilt. The suit charges that they “have failed to conduct their admissions practices on a need-blind basis because all of them made admissions decisions taking into account the financial circumstances of applicants and their families, through policies and practices that favored the wealthy.”

Columbia University is criticized because its School of General Studies, which the suit says enrolls 2,500 undergraduates, doesn’t have need-blind admissions, according to the suit. “The burden of supporting Columbia’s preservation of prestige and financial accumulation therefore falls on those who can least afford it,” the suit says.

The Justice Department brief also cites the suit it filed in 1989 (and won) against the Ivy League universities and the Massachusetts Institute of Technology. The Ivy League universities settled the suit, while MIT fought it and lost.

Representatives of the colleges in the current suit, some of which were in the earlier suit, could not be reached for comment this morning.

Robert D. Gilbert, a lawyer for the plaintiffs, said, “We are very pleased that the Department of Justice has filed this statement supporting plaintiffs on the key issues in this case.”