At some point over the past 244 years, the United States realized that, as a representative democracy, it might be useful to introduce mechanisms meant to reduce the ability of bad actors to skew elections. Writing a candidate’s name on a piece of paper and sticking it in a box works fine for electing a fifth-grade class president, but electing a member of Congress or an actual president should understandably be a bit more complicated. So states developed different but parallel ways of matching votes to voters, making elections much more secure.

So secure, in fact, that fraud by now is rare. But given the eternal political utility of restricting the vote, there’s been an ongoing effort to present fraud as an existent and rampant threat to American elections. And no one has been more enthusiastic about leveling that charge than President Trump.

On Monday morning, he reiterated one of his preferred arguments against expanding mail-in balloting, a practice that has grown since the emergence of the coronavirus earlier this year.

It’s a nifty little argument, pivoting off concerns about foreign interference introduced in 2016 — thanks to Russia’s interference on his own behalf — to suggest that foreign countries would tip the scales by stuffing ballot boxes.

Even a fifth-grade class president, though, can probably identify at least one problem with this theory.

The first is precisely that votes are necessarily correlated to voters. Submitting millions of ballots in general means identifying millions of active voters on whose behalf the ballots should be sent. Trump has repeatedly lifted up a Pew Center on the States report from 2012 delineating bloat in America’s voter rolls. People routinely move or die without updating their status with local registrars of voters, meaning that there are theoretical voters who are either living out of state or not living at all. The 2012 report identified 1.8 million dead voters alone.

The irony, of course, is that the focus on these inactive voters has meant that counties have been more active about culling expired registrations. Los Angeles County was sued by the pro-Trump activist group Judicial Watch, leading it to purge 1.5 million presumably inactive voters. That’s 1.5 million fewer voters for a theoretical foreign power to exploit.

Mind you, a foreign power that obtained a full voter file would not necessarily know any better than the county itself which voters were inactive. So you would get a ton of submitted ballots for voters who were themselves already voting — especially given that turnout peaks during a presidential election year. Meaning a ton of duplicate ballots, quickly exposing the attempted fraud.

None of this, though, is the main reason that Trump’s theoretical fraud would not work. The main reason the fraud wouldn’t work is that casting a ballot isn’t as easy as getting one and turning it in. County governments then validate the ballots against existing information — usually matching a signature by hand — before considering it valid.

In other words, not only would this foreign government need to identify nonvoters or get lucky by not duplicating ballots; it would also have to somehow ensure that the ballots it was submitting didn’t include obviously forged signatures.

How difficult would that be? We asked Patricia Siegel of Siegel Forensics to evaluate.

“It’s my evaluation — according to my own sense of probability, which comes out of my experience — that it’s highly unlikely that it would be done in a mass scale,” she said.

Why? Well, first, the foreign power would need to obtain some sort of copy of what the voter’s signature looks like. Without that, Siegel said, it would be all but impossible to get lucky enough to generate a passable version of a voter’s signature “out of thin air.”

There are ways in which a voter’s signature might be obtained, of course. We sign our names regularly, often on formal legal documents, making it, as Siegel said, “unlikely that someone hasn’t seen [your] signature.” But there’s a difference between obtaining one person’s signature in order to re-create it and obtaining millions.

Perhaps there’s a database storing these signatures that a foreign power could access. The registrar of voters has them all, after all. It’s important to note, though, that obtaining a list of voters is different than accessing the registrar’s database. The former can be purchased in bulk from a third party, which is how candidate campaigns get your address to send you mail. The latter is trickier, requiring hacking into the county system. That is, hacking into hundreds of systems, given our distributed electoral process, to obtain signature files to replicate on mailed ballots — and hacking into all of them without detection.

Siegel said registrars of voters have become more circumspect in making voter signature information available. She used to be able to go to the registrar in Nassau County, N.Y., to compare a signature to a known example. She no longer can.

So if the foreign power obtained those signatures, matched them to voters and mailed them back in, the signatures would then have to be obviously not forged even if they were exact replicas of the originals on file (which, of course, would probably raise eyebrows by itself). For example, they would need to not be obviously printed on the ballot, as opposed to signed by hand. This isn’t as hard to pull off as it might seem, Siegel suggested, but it is still an example of a bar that needs to be surpassed.

Only then do we hit all of the other problems: that the voter is still valid, that he or she has not already voted and so on.

There’s one last problem that doesn’t have to do with the mechanism for voting at all. In 2016, Trump won the electoral college thanks to about 78,000 votes in three states: Wisconsin, Michigan and Pennsylvania. Ask experts a month before the election where the closest races were going to be, and few would have identified those particular states. So this effort to swing the election, which needs to be big enough to be effective but small enough to limit the chance of detection (since detection means potentially invalidating the results) has to be narrowly targeted to places where the need was highest. A foreign power that somehow successfully submits a million fraudulent ballots in Los Angeles might sway a Senate race in that state, but it is not going to affect the presidential results.

Again, America has spent two centuries figuring out how to secure its elections and has come up with safeguards that make the scenario Trump blithely presents as a likelihood an obvious nonstarter. Maybe if Trump’s 14-year-old son wanted to bolster his college applications with a position on student government, a foreign power could deliver the election. Manipulating mail-in ballots on his father’s behalf is a much trickier proposition.