On Tuesday, President Trump dismissed the latest sexual misconduct accusation against his Supreme Court nominee, Brett Kavanaugh. Trump scoffed that Deborah Ramirez, who says Kavanaugh exposed his genitals to her during a drinking game in college, was too “inebriated” and “messed up” to know what happened. It’s reasonable to ask whether alcohol impaired Ramirez’s memory or the memory of Kavanaugh’s other accuser, Christine Blasey Ford. But it’s just as reasonable—and based on current evidence, more warranted—to raise that question about Kavanaugh himself.

Broadly speaking, in the debate over Kavanaugh’s guilt or innocence, there are four possible answers. One is that Kavanaugh is lying. The second is that his accusers are lying. The third is that nobody’s lying: The accusers believe Kavanaugh did what they allege, but he didn’t. The fourth scenario, too, posits that nobody’s lying. On this theory, Kavanaugh believes he didn’t do what his accusers allege, but he did.

The fourth option is worth a closer look. Ford says Kavanaugh drunkenly pinned her down at a teen party, groped her, and tried to pull off her clothes. Ramirez says Kavanaugh stood next to her and dropped his pants when they were drinking with classmates at Yale. Is it possible that Kavanaugh did these things, even if he doesn’t remember them? Is there evidence that makes that scenario particularly plausible in his case? Are there steps that the Senate can and should take to investigate that possibility? The answer to all three questions is yes.

Let’s start with the culture of drinking and partying among Kavanaugh’s high school friends. Numerous peers and classmates have described a routine of “fake IDs,” “unchaperoned parties,” “binge drinking,” “flocking to the house of whoever’s parents were out of town to drink six-packs,” and “Georgetown Prep students engaging in sexual misconduct.” One of Kavanaugh’s teachers says, “The drinking was unbelievable.” A classmate of Ford says, “The boys were pretty brutal. They would do what they could to get you drunk, and do whatever they would try to do to you.” Other students have reported the same.

While it’s reasonable to demand evidence on the other side, there are good grounds in Kavanaugh’s case to believe he could have forgotten.

There was also a culture of booze among Kavanaugh’s college friends. Classmates say “heavy drinking was routine,” and “alcohol-fuelled parties” often led to gross sexual behavior. Kavanaugh’s fraternity loved to party and is remembered for “reviving a beer-drinking competition that college officials had banned from campus.” A photo taken during his frat years shows pledges marching with a flag made of bras and women’s underwear.

Kavanaugh was part of this culture. His friend Mark Judge, who is accused of collaborating in the alleged assault on Ford, has written books and articles that detail extensive drinking in their social circle. In his writings, Judge calls this group “Alcoholics Unanimous.” He describes their school, Georgetown Prep, as “swimming in alcohol.” He depicts house parties like the one at which Ford says she was assaulted. According to Judge, these were informal, unsupervised gatherings at which boys and girls from single-sex schools could party together whenever “someone’s parents were going away.” For boys, the goal was sex. Judge writes: “Most of the time everyone, including the girls, was drunk. If you could breathe and walk at the same time, you could hook up with someone.”

Judge specifically describes incidents in which he “blacked out” and later learned that he had done things he didn’t recall. In one case, he woke up “terrified of what I could have done during the blackout.” He frets, “I could have done anything and not know it—I could have murdered somebody.” In another case, a friend informed him that during an episode of which Judge had no memory, Judge had “tried to make it with one of the bridesmaids.” Judge pleaded with his friend: “Please tell me I didn’t hurt her.” Judge’s ex-girlfriend says he once told her how he and other boys used a drunk woman for sex. Judge denies that he did this. But in one of his books, he confesses that when he drank, “It was as though there was a different version of myself—Mr. Hyde—who had taken over my body, and I couldn’t stop him.”

Judge’s confessions about what he did while drunk—or believed he was capable of doing while drunk—are consistent with Ford’s account of what Judge and Kavanaugh did to her. Judge says he doesn’t remember any of it. Of course he doesn’t. That’s his pattern. When he drinks, he behaves aggressively and doesn’t recall what happened. According to Ford, Judge and Kavanaugh drank heavily before the assault. So there’s a prima facie case that Judge could have done what Ford alleges. But what about Kavanaugh?

Kavanaugh’s entry in his high school yearbook makes clear that he drank. It’s facetious, but only in tone. He noted his membership in the “Beach Week Ralph Club” and called himself the treasurer of the “Keg City Club.” He also claimed to belong to the “Rehobeth Police Fan Club”—apparently a reference to a beach community where rowdy boys from Georgetown Prep got into trouble. Judge has described these beach trips as a “bacchanalia of drinking and sex, or at least attempts at sex.”

As a freshman at Yale—the year after Ford says Kavanaugh assaulted her—Kavanaugh drank heavily, according to his roommate. “I would see him as he returned from nights out with his friends,” says the former roommate, James Roche. He recalls Kavanaugh as “a notably heavy drinker, even by the standards of the time.” Roche describes Kavanaugh “frequently drinking excessively and becoming incoherently drunk.”

Kavanaugh has also admitted to heavy drinking at his next stop, Yale Law School. In a speech four years ago, he recalled organizing “a night of Boston bar-hopping,” with students “doing group chugs from a keg” and “falling out of the bus.” Kavanaugh went on to describe a night on which “we had more than a few beers,” then “we had a few drinks” at a banquet, then a friend “lost his balance and fell into the table,” breaking it, and a professor “came to the rescue … and got my friend some more beers.”

Given this pattern of inebriation, could Kavanaugh have blacked out? Could he have done bad things and forgotten them? Again, evidence suggests he could. In an autobiographical novel about their high school years, Judge depicts a character named Bart O’Kavanaugh who “passed out on his way back from a party.” And according to Roche, during the year after the alleged assault on Ford, Kavanaugh—who was “normally reserved” when sober—became “aggressive and belligerent when he was very drunk.”

Kavanaugh brushes off questions about his drinking. “Yes, people might have had too many beers on occasion,” he told Martha MacCallum in a Fox News interview on Monday. “I think all of us have probably done things we look back on in high school and regret or cringe a bit, but that’s not what we’re talking about,” said Kavanaugh. “I’ve never sexually assaulted anyone.” When MacCallum noted Roche’s comments about Kavanaugh’s inebriation in college, Kavanaugh narrowed the question, noting that Roche didn’t specifically corroborate the incident Ramirez reported. Then MacCallum asked: “Was there ever a time that you drank so much that you couldn’t remember what happened the night before?” Kavanaugh replied: “No, that never happened.”

That won’t cut it. A person who drinks to the point of passing out, and who experiences personality changes when he’s drunk, can’t reliably say what he did or didn’t do while intoxicated. And while it’s reasonable to demand evidence on the other side—you can’t just claim that somebody forgot what happened and presume him guilty—there are good grounds in Kavanaugh’s case to believe he could have forgotten. He had major alcohol issues from high school through law school. He has described drinking more than he could remember. He has been depicted, by people who knew him well, as “aggressive and belligerent when he was very drunk,” and as having passed out.

On Thursday, Kavanaugh faces a Senate hearing about Ford’s allegations. He will try to draw a line. At a rehearsal with White House aides last week, he “grew frustrated” with questions about his drinking and his sexual behavior, according to the Washington Post. “I’m not going to answer that,” he said. Judge doesn’t want to answer questions either. The Republicans who control the committee are planning to leave Judge out of the hearing.

That’s unacceptable. The alcohol theory is arguably the most plausible explanation of what happened. It’s less crazy than Ford inventing a story and putting herself through hell so Trump can nominate a different conservative judge to the Supreme Court. It’s less crazy than two different women developing false memories about the same man. It’s less crazy than Kavanaugh being a total fraud who has conned friends and colleagues into thinking he’s a decent guy. And even if you prefer one of the other theories, this one is sufficiently plausible and well supported to merit scrutiny.

If the committee won’t delegate this job to the FBI, senators must do it themselves. Ask Judge and Kavanaugh about their history with alcohol. Talk to the people who drank with them or saw them drunk. If you think alcohol could have corrupted Ford’s memory or Ramirez’s memory, ask about their drinking too. This is an investigative avenue with a strong evidentiary basis and many potential witnesses, and it puts everyone’s denials in doubt. To confirm Kavanaugh without checking it out would be a betrayal of justice.