Just six weeks ago, Sen. Elizabeth Warren, D-Mass., penned an op-ed for The Washington Post dismissing any concerns about voter fraud and election insecurity as the whining of a soon-to-be-defeated Donald Trump.

What a difference a month makes.

Now, liberal groups, having forced a recount in Wisconsin, are rallying behind defeated Green Party presidential candidate Jill Stein's efforts to expand the effort to Michigan and Pennsylvania, which, like Wisconsin, helped hand the White House to President-elect Trump. Their theory: the election may have been rigged by Russian hackers or some other troublemakers.

It's remarkable - and welcome - that the political left has finally awoken to the reality that American elections are vulnerable to acts of fraud. Conservatives have been saying so for years. Yet this latest move - which lacks any supporting evidence - seems more a cynical political ploy with the undertones of a Nigerian scam than an actual awakening to the reality of voter fraud.

After all, consider the wildly different reactions from many on the left to dueling claims of voter fraud by Stein and president-elect Trump. Stein has been embraced as a crusader for, in her words, promoting a "voting system we can trust." But the president-elect's suggestion that he was robbed of a popular vote victory by millions of illegally voting non-citizens was met with scorn. Many of the same outlets that had lent weight to Stein's claims of Russian hacking once again insisted that voter fraud simply does not exist.

There is little direct evidence that illegal ballots were cast in numbers significant enough to deny the president-elect a lead in the popular vote. But to deny even the possibility that this type of fraud occurs is laughable because it is demonstrably false.

Over the last two years, scholars at The Heritage Foundation have gathered the evidence that many insist does not exist: proof that old-fashioned voter fraud is real. Our voter fraud database now details nearly 450 confirmed examples (encompassing 721 actual criminal convictions), including in-person fraud, absentee ballot fraud, duplicate voting, illegal felon voting and, yes, even non-citizen voting.

The tales vary. In Alabama, Olivia Lee Reynolds conspired to ensure that her boyfriend, Dothan City Commissioner Amos Newsome, won his 2013 campaign. Reynolds filled out voters' absentee ballots for them, depriving them of their chance to vote for another candidate. Newsome won 96 percent of the absentee vote and carried the election by a scant 14 votes, though he lost the in-person vote. Reynolds was convicted of 24 counts of voter fraud.

In Ohio, a poll worker named Melowese Richardson voted twice in the 2012 election. In three other elections, Richardson voted in the names of others, including her comatose sister. She was convicted and sentenced to serve five years in prison.

Rogelio Mejorada-Lopez, a Mexican citizen, successfully registered and voted illegally in three elections in Alaska. He was charged with three counts of unlawfully voting as a non-citizen, and pleaded guilty.

These cases are just a small sampling from the Heritage database, which is itself the tip of the proverbial iceberg. Most states lack the procedural tools needed to detect voter fraud, either before or after it occurs. Few of our nation's overworked prosecutors devote the resources needed to prosecute these cases, especially after elections are over. While easy to commit, most voter fraud simply goes undetected and, therefore, unpunished.

While we cannot with any certainty quantify the scale and scope of election fraud, evidence suggests that it has the potential to be significant. According to a 2012 Pew study, one out of every eight voter registrations is inaccurate or out of date, and 2.8 million people are registered to vote in more than one state.

With these facts in mind, there are many wiser avenues, besides politically motivated recounts, into which Americans should channel their election-integrity energies. Pushing for voter identification laws, for states to routinely audit their voter rolls and for officials to aggressively prosecute fraudsters would all help to deter and prevent election fraud. And, because concerns about hacking are not unwarranted, the country should avoid any proposals to transition to online voting.

Elections are the fundamental, foundational core of our democracy. That foundation is eroded every time a fraudulent ballot is cast. The problem is serious. It deserves serious solutions, not political stunts.