We’re three weeks from Election Day, and Donald Trump has resorted to the old cannard of voter fraud.

The Republican presidential nominee has doubled down with his contention of a “rigged” election, suggesting that voter fraud is rampant and likely to occur at the polls and beyond.

This isn’t a new idea, nor is it a true one. Similar concerns were raised by Sen. John McCain (R-Ariz.) when he was a candidate, and other Republicans before and since, often in support of restrictive voter ID laws that tend to diminish turnout. Yet nationally, multiple studies have concluded that incidences of voter fraud are scant.

A report on the issue by the Brennan Center for Justice found miniscule rates of fraud in recent elections from the 1990s to 2007 where fraud was alleged. In 2014, a Washington Post report found 31 credible examples of impersonation fraud between 2000 and 2014 (out of more than a billion ballots cast). Judicial opinions bolster these findings.

Truly rigging an election would take far more than these handful of cases, and would amount to a massive collusion among poll-workers, police and bipartisan statewide elections officials. But that hasn’t stopped repeated fraud allegations from Trump and beyond.

The fear of voter fraud never goes away

Last week, for example, conservative anti-corruption non-profit Project Veritas (which has been accused of selective editing in the past) released a secret recording showing Manhattan Board of Elections Commissioner Alan Schulkin ranting at a 2015 Christmas party about “a lot of voter fraud.”

Schulkin, a Democrat, points to “certain neighborhoods in particular,” where minority voters are bussed from “poll site to poll site.” He says voters should be required to show ID, and worries somewhat inexplicably about the security of the city’s new municipal ID system. He has since amended his comments, saying he should have said “potential” voter fraud. He didn’t point to any specific instances, and the video drew condemnations from the mayor and City Council members who oversee BOE operations.

The BOE had no comment on the video. A spokeswoman said the board didn’t have numbers of fraud investigations or substantiated cases available.

But the data tell a clear picture: In 2002 and 2004, allegations of between 400 and 1,000 voters double-voting in New York and Florida were substantiated in two cases, according to the Brennan Center. In the same years, 2,600 deceased New Yorkers were alleged to have “cast” ballots, though no fraud was found by journalists investigating some of the claims.

To be sure, scattered instances of voter fraud are always possible; and the BOE is not impervious to clerical errors and sloppiness (see: improperly purged voter lists during this cycle’s April primary).

What would it take to actually rig an election?

But the kind of vast fraud Trump is talking about would take a lot of work and concerted effort to cast a fraudulent ballot in person even if you wanted to orwere your average immigrant here illegally inexplicably burning with desire for “committing a felony,” as Neal Rosenstein of the New York Public Interest Research Group put it.

First of all, you need a drivers’ license number or last four digits of your Social Security number to register to vote.

If you don’t have those, you have to sign an affidavit confirming right to vote. Lying is punishable by jail time or up to $5,000 in fines. Plus, you’d then have to show a form of ID at the polls. That can include the IDNYC, which itself has rigorous security requirements to obtain, subject to multiple layers of screening and authentication.

Poll workers are required by the state constitution to identify voters by comparing their signatures on Election Day to their signatures on record. Voters’ ages are also listed. Large-scale vote manipulation would require those workers to knowingly and willingly mark fake votes, which no ID law would guard against (and would also be hard to guarantee nation-wide).

And for those like Trump who intimate even wider allegations of “rigged”: physical ballots are sealed in a box and brought to borough election boards by police officers. There, the ballots are checked against electronic results to make sure the count is accurate.

Not exactly rife for rigging either.