This claim that millions of illegal immigrants voted is itself the result of a random tweet. On November 13, Gregg Phillips, a former Texas Health and Human Services Commission deputy commissioner, tweeted about there being three million votes that were cast by noncitizens. He has been asked to provide evidence, without having done so.
Regardless, the story was picked up by the conspiracy-theory hawking site InfoWars, a story that was linked out at the top of the Drudge Report on November 14.
The rumour-debunking site Snopes looked at Phillips' claim and found no evidence for it.
Also, Phillips made his claim only five days after the election. Meaning that his data apparently came in before any number of states certified their results. And one examination of a database of voter fraud found 56 cases of noncitizens voting, over 11 years.
But this isn't rooted in logic. Trump has been complaining about the voting process for years, and apparently winning the presidency isn't going to change that.
That's the broader point that's worth raising.
The President-elect of the United States is willing to embrace unproven and highly questionable data to raise questions about the electoral process even after he won simply to soften the blow of losing the popular vote.