In Virginia, non-citizens have not only succeeded in registering to vote by the thousands, many have actually cast ballots in recent elections. That’s the startling truth revealed in the latest edition of Alien Invasion, a report released last week by The Public Interest Legal Foundation.

Like most truths, this one was not easy to come by. Old Dominion election officials made it as hard as possible for the foundation to get access to what are supposed to be public voting records.

But thanks to the group’s dogged perseverance, we now know that the liberal mantra that “voter fraud is virtually nonexistent” is flat out wrong.

PILF’s findings regarding massive voter registration irregularities are drawn from voting records that states must keep pursuant to the National Voter Registration Act, also known as the “Motor Voter” law.

The NVRA mandates that states allow individuals applying for driver’s licenses to simultaneously register to vote. There is a problem, though. States do not extend licenses only to citizens. Legal resident aliens — and even illegal immigrants in states like California — are granted driver’s licenses as well.

The only thing standing between these non-citizens and the voting rolls is a box that must be checked attesting to their citizenship. Some courts have wrongly interpreted the NVRA to hold that states are not permitted to seek any proof of citizenship and must instead take the claim at face value.

Unsurprisingly, this porous barrier has allowed thousands of ineligible voters to slip through and onto Virginia’s voter rolls.

PILF found that since 2011, 5,556 non-citizens successfully registered to vote, only to be removed when Virginia election officials subsequently discovered their alien status.

Don’t read that as an indication that Virginia has a functioning system in place to protect election integrity. It does not. As PILF notes, the only reason most of those 5,556 alien voters were identified was that they outed themselves as non-citizens after first indicating on their voter registration forms that they were, in fact, Americans.

That discrepancy, not an affirmative effort on the part of the state to verify citizenship, prompted their removal.

Without adequate provisions in place to safeguard the registration process, non-citizens have apparently voted by the thousands.

According to PILF data, since 1988 some 1,852 non-citizens succeeded in voting 7,474 times in Virginia. Each illegally cast vote is likely a criminal act, yet PILF turned up no evidence that any of these cases was referred for prosecution.

Such inaction deserves sharp criticism. In what other realm of potential criminal misconduct does the government take such a lackadaisical approach to enforcement? Imagine if cops did not pursue bank robbers, instead waiting for them to slip up by citing “theft” as their primary source of income when filing tax returns.

The lack of transparency over this issue is also alarming. Indeed, state election officials resisted disclosing all manner of public records requested by PILF — records that made it abundantly clear that ineligible ballots were being cast. PILF was forced to go to court to obtain these records.

PILF’s laudable efforts have provided yet more evidence of the supposedly non-existent problem of electoral fraud.

The Heritage Foundation, meanwhile, maintains a lengthy and growing database of proven voter fraud that has resulted in criminal convictions or overturned elections.

The PILF report presents literally thousands of additional cases that could be added to that database — if government prosecutors actually went to the trouble of prosecuting these cases, as they have an obligation to do.

The integrity of the electoral process is essential to the legitimacy of the political process as a whole. This is especially true in a swing state where elections decided by mere hundreds of votes can have an outsized impact on national politics.

But even if that were not the case, every eligible voter should be able to cast a ballot secure in the knowledge that his or her vote will not be nullified through the actions of fraudsters and thieves, or non-citizens who illegally vote.

Unfortunately, Virginia voters have no such assurance. Legislation to secure elections against fraud of all types — including sensible measures like voter identification laws and programs to root out voters registered in multiple states — has been consistently vetoed by Gov. Terry McAuliffe.

Other states are taking election fraud seriously. It is eminently clear that it is time to replace politically-motivated obstinacy with a full-throated defense of electoral integrity in Virginia.