The Foundation for Individual Rights in Education has sent a letter to the Education Department formally opposing affirmative consent, or "yes means yes," policies at colleges and universities.

FIRE has written against the use of yes-means-yes policies previously, as the rules define nearly all sex as rape and provide little recourse for accused students to prove their innocence.

"Given [the Education Department's Office for Civil Rights'] repeated acknowledgment that colleges' and universities' implementation of Title IX should not impinge on students' due process rights, the agency should clearly and publicly censure any consent standard — including the 'affirmative consent' standard — that seriously undermines an accused student's ability to defend himself or herself in a fair hearing," wrote FIRE's senior program officer, Susan Kruth.

Kruth pointed to an "insufficient notice of what behavior is prohibited or required" as one of the problems with affirmative consent. Kruth notes the court case Grayned v. City of Rockford, in which the Supreme Court wrote that laws must "give a person of ordinary intelligence a reasonable opportunity to know what is prohibited, so that he may act accordingly."

Affirmative consent standards, Kruth argues, do not provide such an opportunity. She wrote that the policies "suffer from being both overly broad and vague," and that the policies themselves are disputed even among supporters.

"For example, California's affirmative consent bill explicitly requires that consent be 'ongoing throughout a sexual activity,'" Kruth wrote. "But there is disagreement even among affirmative consent proponents as to what this means — whether, for example, it requires asking for permission before touching each body part."

New York, the only other state to pass a law requiring that affirmative consent be the standard at all its colleges and universities, has a similar problem. The state requires that consent be "knowing," but doesn't make clear what each party must "know" or what communication — verbal or nonverbal — effectively communicates such knowledge.

Essentially, this makes nearly all sex nonconsensual unless no one files a report.

The vagueness and desire to stop campus sexual assault has led to some truly tricky policies, as Kruth noted. At Ohio State University, students engaging in sexual activity must agree on the "who, what, where, when, why and how" of any encounter. "Consenting adults do not always agree on why they are engaged in sexual activity, but that should not render such activity sexual violence," Kruth wrote.

"Affirmative consent standards' vague and overbroad language leaves students both unable to gauge what behavior might land them in a campus tribunal and unable to defend themselves should they be charged with sexual assault," Kruth wrote.

And proponents of the policies don't seem to care. A co-author of the California law was asked how an accused student was supposed to prove that he followed the policy. She replied: "Your guess is as good as mine."

As Kruth noted, there is nothing wrong with colleges and universities encouraging more communication between sexual partners, but threatening punishment if one doesn't adequately navigate the vague minefield is inexcusable.

Kruth also took affirmative consent standards to task for placing the burden of proof on accused students. In traditional cases involving crimes (and let's never forget that sexual assault is a crime), the burden is on the prosecution — the accuser —to prove that a crime has been committed. But with sexual assault on college campuses, if the accused student presents no evidence and doesn't tell his side of the story, he will most certainly be found responsible.

Such burden-shifting has already been deemed "flawed and untenable" by a judge in Tennessee. The judge wrote that, "Absent the tape recording of a verbal consent or other independent means to demonstrate that consent was given, the ability of an accused to prove the complaining party's consent strains credulity and is illusory."

Kruth pointed out that even if an accused student has followed the vague affirmative consent laws perfectly, proving he did so is nearly impossible, especially when an accusation comes weeks, months or even years after the encounter.

What these laws do, essentially, is teach young men — the most likely targets of accusations — to distrust their partners and treat every encounter as if they will later be accused of a crime. And truthfully, the only way to prove consent was obtained is by video tape, which creates its own host of problems.

"Under the affirmative consent standard, campus disciplinary hearings determine not whether the complainant actually consented — in fact, the [Tennessee] court noted that the Chancellor 'made no finding that [the complainant] did not consent' — but whether the accused student can prove to a panel of strangers that the complainant consented," Kruth wrote (emphasis original). "This crucial distinction demonstrates that affirmative consent policies effectively prohibit some sexual activity that is in fact consensual and therefore not sexual assault under the law."

Again, affirmative consent policies make nearly all sex illegal, unless someone can prove it was legal.

Kruth also noted that affirmative consent policies do not come with due process protections for accused students, making them "guilty until proven innocent." Campus tribunals lack rules of evidence and disallow cross-examination (indeed, the Education Department tells them to), subpoena power, testimony given under oath, the right to be represented by an attorney and many other due process protections. That, coupled with a low standard of evidence (adjudicators have to be just 50.01 percent convinced the accuser didn't consent), and schools have a recipe for punishing innocent students.

Kruth wrote that the Education Department had emphasized due process rights previously, and needs to do so again.

"The Constitution … guarantees due process to students in public and State-supported schools who are accused of certain types of infractions," the Department wrote in 2001. In the Department's 2011 "Dear Colleague Letter," which has been used to force schools to adjudicate felonies as disciplinary matters, public and state-supported schools were again reminded that they "must provide due process to the alleged perpetrator." Affirmative consent standards eviscerate that due process.