We just saw due to a Judicial Watch suit, 1 1/2 million people purged from the voter rolls in Los Angeles County. Even if only 10% of them voted last election, it was enough to decide Maxine Waters over her opponent. If all 1.5 million did vote, there in 1 single county was half the total Clinton supposedly won the popular vote by.
Disgusting as it seems, the illegal vote could definitely affect the winner in a popular vote contest. But then, that's why the Dems fight the wall, and voter ID laws. Their legal base isn't big enough to win much of anything. So they need these extra illegal votes.