One of his clients sued the Education Department last year, saying he had been found responsible for sexual assault only because the University of Virginia, where he was a law student at the time, had switched to the lower standard. According to his lawsuit, the accuser said that she had been unable to consent to sex because of alcohol consumption, while he claimed the accuser did not even appear to be intoxicated, let alone incapacitated.

There are likely to be other immediate effects of Ms. DeVos’s moves.

She eliminated a requirement that investigations be completed in 60 days, now suggesting that the time frame be “reasonably prompt.” The department will also allow mediation — sessions in which an accuser and accused hash out their differences — if both sides agree. Mediation was not permitted under the Obama administration guidelines, on the belief that women would feel pressure to participate.

Christina Hoff Sommers, a scholar with the conservative American Enterprise Institute who has written about sexual assault, applauded the administration’s decision to permit mediations, saying that some victims were not necessarily seeking a full-blown investigation and a trial. “I think it’s misguided to depict the average undergraduate in terms of oppressor and oppressed,” she said.

But Cari Simon, a Washington lawyer who represents sexual assault victims, said that colleges could use mediation to avoid addressing serious accusations. “Mediation allows schools to sweep sexual violence under the rug, treating it as a misunderstanding between students,” she said.

The Obama administration investigated hundreds of colleges based on student complaints that they had failed to adequately enforce sexual assault regulations. The Education Department had forced a number of colleges to change their procedures by threatening loss of federal funding.

Department officials, in a conference call with reporters on Friday, indicated that they might discontinue some of the 350 or so active investigations if those cases hinged on rules that have now been rescinded.

Those rules — delivered in a 2011 “Dear Colleague” letter sent to colleges by the Obama Administration that laid out how sexual assault complaints were to be handled, as well a 2014 follow-up — came in response to accounts of colleges failing to take complaints seriously, letting untrained employees botch investigations and meting out little discipline.