Brett M. Kavanaugh, President Trump's Supreme Court nominee, pauses as he testifies before the Senate Judiciary Committee on Capitol Hill in Washington on Sept. 5. (Jacquelyn Martin/AP)

In testimony to be delivered before the Senate Judiciary Committee tomorrow, Judge Brett M. Kavanaugh denies he ever sexually assaulted Christine Blasey Ford or anyone else. But he acknowledges that he was “not perfect” during his high school days. “I drank beer with my friends, usually on weekends. Sometimes I had too many,” he writes.

The fate of Kavanaugh’s Supreme Court nomination hinges in part on what happened during the judge’s late high school and early college years in the 1980s. Kavanaugh’s own admission of occasional heavy drinking, along with boozy tales from accusers and people who knew him, underscore a key way that the early 1980s were unique in contemporary American history: Long-running federal survey data show that those years were a high-water mark for teenage drinking.

The chart above tells the story. In the late 1970s and early 1980s, upward of three-quarters of male high school seniors drank alcohol on a monthly basis. Since that period, those numbers have fallen by more than half, to 36 percent in 2015.

The other striking feature of this chart, which uses data from the federal Monitoring the Future survey, is how the early 1980s were marked by a distinct gender gap in drinking habits that has all but disappeared today. In 1982, for example, male 12th-graders were about 9 percentage points more likely to drink in a given month than females. But today, the percentages are virtually identical.

A similar pattern is on display when it comes to binge drinking, which the survey defines as consuming five or more drinks in a row. In 1982, about half of male high school seniors and 30 percent of females reported binge drinking at least once in the prior two-week period. Again, both numbers fell by more than half by 2015, with the previously large gap between men and women shrinking substantially.

Figures like these are crucial for understanding the social context of Kavanaugh’s high school and college days. Drinking, even heavy drinking, was much more common among teenagers than it is today. Kids who drink heavily put themselves and others at risk for all manner of harm — drunken driving accidents, physical altercations, unprotected sex and poor school performance, to name just a few.

But one of the less-appreciated risks of alcohol consumption is sexual assault. According to the National Institute on Alcohol Abuse and Alcoholism, more than half of sexual assaults involve alcohol consumption by the perpetrator, victim or both. Studies of college campuses have found that higher rates of binge drinking are associated with higher rates of sexual assault.

This isn’t to say that alcohol, in and of itself, causes sexual assault. Plenty of men drink heavily and never sexually assault anyone, and plenty of assaulters commit their crimes without having had anything to drink.

But laboratory experiments have demonstrated that alcohol can enable sexual assault by removing inhibitions among men who may be predisposed to commit it. As FiveThirtyEight’s Maggie Koerth-Baker put it in a report Wednesday summing up the latest research, “when a man feels entitled to assault someone, he may get drunk before he does it, but the decision to act was ultimately his alone.”

Circling back to the early 1980s, it’s clear that the heavy drinking so prevalent among teens at the time contributed to an environment that was a lot more dangerous and high-risk than what teens today have to deal with. And it’s likely that untold thousands of today’s adults are still grappling with the consequences of what they did, and of what was done to them, at the booze-soaked parties of yesteryear.