The sexual misconduct allegations against Supreme Court nominee Brett Kavanaugh date back to his high school and college years — decades ago.

When journalists write about incidents that occurred long ago, especially serious allegations such as sexual misconduct, a key goal is to find people who will say that they heard about the incident at the time. Such contemporaneous accounts are essential to establishing the credibility of the allegation because they reduce the chances that a person is making up a story for political purposes.

The sexual claims against former president Bill Clinton, especially those of Paula Jones and Juanita Broaddrick, and against President Donald Trump, such as those of Natasha Stoynoff, have credibility precisely because so many people attest they heard about the incidents at the time.

The central charge against Kavanaugh — that he sexually assaulted Christine Blasey Ford while intoxicated during a party — lacks this element. Ford said she kept quiet about the incident until recent years. But she has provided witnesses who say she told them about the allegation before Kavanaugh was nominated for the Supreme Court.

Meanwhile, two other women have also emerged with similar allegations against Kavanaugh, also in the context of heavy drinking. He has adamantly denied that he ever attacked any woman.

Here's a guide to the allegations and what evidence has been presented.

Christine Blasey Ford

Her allegation: In the early 1980s, when she was 15 and Kavanaugh was 17, she said that Kavanaugh and a friend, both "stumbling drunk," forced her into a bedroom during a gathering of six teenagers at a private home. While his friend watched, she told The Washington Post, "Kavanaugh pinned her to a bed on her back and groped her over her clothes, grinding his body against hers and clumsily attempting to pull off her one-piece bathing suit and the clothing she wore over it. When she tried to scream, she said, he put his hand over her mouth." She eventually escaped from the room when the friend, identified as Mark Judge, jumped on them and then tumbled on the floor. She said she did not tell anyone about the attack at the time. Her lawyers released a copy of a polygraph exam she took Aug. 7 that indicated that she was not being deceptive.

Corroborators: No contemporary corroborators.

Other witnesses:

Russell Ford, her husband since 2002. He said in an affidavit that he learned that she had been the victim of sexual assault around the time of their wedding. In 2012, during couples' therapy, she revealed that she had been "trapped in a room and physically restrained by one boy who was molesting her while another boy watched ... I remember her saying that the attacker's name was Brett Kavanaugh." (Ford provided The Post with therapist notes from the couples' therapy in which she reported that she was attacked by students "from an elitist boys' school" who went on to become "highly respected and high-ranking members of society in Washington.")

Adela Gildo-Mazzon, a friend. In an affidavit, she said that during a meal in June 2013, Ford, "visibly upset," told her that she had been "almost raped by someone who was now a federal judge. She told me she had been trapped in a room with two drunken guys, and that she then escaped."

Keith Koegler, a close friend. In an affidavit, he said he learned in 2016 that she had been the victim of sexual assault. On June 29, he said, she wrote him an email in which she said the person who assaulted her was Trump's favorite for a Supreme Court nomination.

Rebecca White, a friend. In an affidavit, she said that in 2017, Ford told her that when she had been a young teen, she had been assaulted by an older teen, "now a federal judge."

Reaction: Kavanaugh "categorically and unequivocally" denied he ever was involved in such an assault. He released his calendar for the summer of 1982 to indicate that he had attended no such small gathering. Other people that Ford named as being present at the party, including Judge, said they had no recollection of any such party or such an attack.

Deborah Ramirez

Her allegation: She told the New Yorker that 35 years ago at Yale University, "Kavanaugh had exposed himself at a drunken dormitory party, thrust his penis in her face, and caused her to touch it without her consent as she pushed him away." She said she had drunk a fair amount of alcohol but remembered a male student shouting, "Brett Kavanaugh just put his penis in Debbie's face." She said she had remained silent about the incident for many years because she blamed herself for drinking too much.

Corroborators: None publicly identified. The New Yorker and the New York Times could not confirm with any eyewitnesses that Kavanaugh was present at the party. An unidentified classmate said that he is "one-hundred-per-cent sure" that he was told at the time that Kavanaugh was the student who exposed himself to Ramirez. "The story stayed with him, he said, because it was disturbing and seemed outside the bounds of typically acceptable behavior, even during heavy drinking at parties on campus," the New Yorker reported.

Other witnesses:

James Roche, Kavanaugh's freshman year roommate. He said in a statement that while "I did not observe the specific incident in question, but I do remember Brett frequently drinking excessively and becoming incoherently drunk." He added that he was close friends with Ramirez and "I cannot imagine her making this up."

Reaction: Kavanaugh denounced the allegation as a smear. Other students who Ramirez said were involved in the drinking game disputed her version of events.

Julie Swetnick

Her allegation: In a sworn declaration, she said that in 1981-1983, she observed Kavanaugh drinking excessively at house parties and engaging "in abusive and physically aggressive behavior toward girls." She claimed that Kavanaugh and others would get girls inebriated so they could be "gang raped" in side rooms at house parties by a "train" of numerous boys. "I have a firm recollection of seeing boys lined up outside rooms at many of these parties waiting for their 'turn' with a girl inside the room. These boys included Mark Judge and Brett Kavanaugh." She added that in 1982, she was a victim of a "gang rape" at which Kavanaugh was present. But she did not say he participated in it and provided no details about where the alleged rape took place.

Possible related allegation: Elizabeth Rasor, a former girlfriend of Judge at Catholic University, said that Judge told her about an incident in which he and other boys took turns having sex with a drunk woman. "Rasor said that Judge seemed to regard it as fully consensual," the New Yorker reported. "She said that Judge did not name others involved in the incident, and she has no knowledge that Kavanaugh participated." Judge categorically denies her account. Rasor has told the Judiciary Committee that she would be willing to talk to the FBI about the incident.

Reaction: Kavanaugh denied Swetnick's claims, saying it was like something out of the "Twilight Zone."

This story first appeared in The Washington Post.