Near midnight on a Saturday, eight people spilled out of a fraternity house, including a woman who walked unsteadily as she held a red Solo cup, and a man who paused to relieve himself on a tree. They called up to the open third-floor window of another frat house, where a man in a drinking game teetered alarmingly against the sill.

They and dozens of others converged on a crowded house near campus, where one young man urinated on an overturned lawn chair in the yard, another propped up a woman who repeatedly said, “Don’t let me throw up,” and in a basement, students danced to throbbing hip-hop music or played beer pong on plywood tables. Later, clusters of students straggled out past a forest of empty bottles and cups, with many of the men — and a few of the women — making their way noisily back to the frat houses for the night.

Fraternities have no monopoly on this kind of revelry, or on serious misconduct — similar ills have plagued sports teams, marching bands and even debate and glee clubs — and defenders of Greek life argue that there will be no less trouble without it. They also note that students who belong to fraternities and sororities have higher graduation rates than their peers, that the groups do volunteer work, and that alumni are known for loyalty to their organizations and colleges.

As a result, administrators do not denounce fraternities outright, even while they try to rein them in.

“I think we have to be very careful before we blame the Greeks,” said Patricia Telles-Irvin, the university’s vice president for student affairs. “They’re so visible that they get easily targeted. I’m not saying they’re so innocent, but other student organizations that are hazing and drinking aren’t really in the limelight as the Greeks are.”

In this school year, Northwestern, like many of its peers, has toughened its policies against hazing and sexual assault, and planned a hazing prevention task force and a student survey on campus social issues. But there is no plan to restrict fraternities.