What happens when the statistical basis for a massive, nationwide legislative push crumbles into dust? Absolutely nothing, if the subject is sexual assault on campus.

This year, more than half the states in the country considered legislation dealing with sexual assault on college campuses. California and New York enacted affirmative-consent policies, Connecticut and Virginia announced new laws intended to prevent sexual violence on campuses and last year President Obama created a task force designed to deal with what liberal political elites claimed was a startling rise in sexual assault.

But the very studies these politicians relied on don’t say what they have claimed — yet the “yes means yes” juggernaut rolls on.

A study by prominent psychologist David Lisak, “Repeat Rape and Multiple Offending Among Detected Rapists,” has been used by the federal government, schools and activists to justify policies slanted against the accused.

The report purportedly showed campus rapists as serial predators. “This report analyzes the most recent, reliable data about rape and sexual assault in our country,” Obama pronounced. The recent documentary “The Hunting Ground,” a film about campus “rape culture,” relies heavily on Lisak.

But, as a Reason Magazine investigation revealed, Lisak didn’t conduct the study himself. He pooled data from four separate studies directed by others at the University of Massachusetts-Boston between 1991-1998. The sample size was 1,882 men, ranging in age from 18-71. Of this group, the average subject was 26.5 years old — not exactly the age of the typical college student. What’s more, according to the university’s demographics, most students are commuters and don’t live on campus.

On the four surveys Lisak used, the bulk of the questions deal primarily with childhood experiences — only five questions asked about sexual violence possibly committed by the respondents as adults. Based on their responses, only 120 respondents may have committed or attempted rape, and of that number, a mere 76 qualified as repeat offenders, according to Lisak’s definition.

None of the surveys dealt with campus sexual assault. None of the questions “specifically ask[ed] about violence committed by or against students,” Reason reports.

Hardly a statistic strong enough to prove the serial-rapist claim.

Another frequently touted statistic, also asserted by President Obama as well as Gov. Cuomo, is the claim that one in five women on college campuses in the United States has been sexually assaulted or raped.

The statistic is derived from a 2007 study conducted by the National Institute of Justice, a division of the Justice Department, and directly studies campus sexual assault, unlike Lisak’s study.

But there are holes in this research, as well.

For starters, the study was conducted at “two large public universities, one in the South and one in the Midwest,” and the sample size was 5,446 undergraduate women — a “relatively low” response rate, two of the researchers told TIME.

The survey included women who had suffered rape and experienced other types of sexual assault, “such as forced kissing or unwanted groping of sexual body parts,” and of the women surveyed, 19 percent reported experiencing some form of sexual assault.

According to the two researchers, “To limit the statistic to include rape only, meaning unwanted sexual penetration, the prevalence for senior undergraduate women drops to 14.3%, or 1 in 7” at the universities studied.

The researchers said themselves that “there are caveats that make it inappropriate to use the 1-in-5 number in the way it’s being used today, as a baseline or the only statistic when discussing our country’s problem with rape and sexual assault on campus” and warned that “the 1-in-5 statistic is not a nationally representative estimate of the prevalence of sexual assault.”

A study conducted by the Department of Justice, released in late 2014, found that the actual rate of sexual assault of females on college campuses is 6.1 per 1,000 students — or about one-half of 1 percent. Plus, non-students are 25 percent more likely than students to suffer sexual assault — the rate for them is 7.6 per 1,000 people.

Those facts aren’t getting in school administrators’ way, however.

The University of Minnesota announced its affirmative-consent policy will be made official by the time school starts in September. And last week, California passed a law giving state community colleges jurisdiction in off-campus incidents of “sexual assault and sexual exploitation,” according to one lawmaker.

The desire to prevent campus rape is noble. Lawmaking based on false statistics, goosed numbers and ginned-up narratives is anything but.

Madison Iszler is a college student in New York and a former Post summer intern.