Mitt Romney won white voters by 20 points in today’s presidential election, according to exit polls, which is the same margin that Ronald Reagan won that demographic by in his 1980 landslide over Jimmy Carter. But given that white voters are a smaller percentage of the electorate these days and he’s doing poorly among minority voters, Romney is on the cusp of losing the election.

In 1980, Reagan won white voters 56 percent to 36 percent, with third party candidate John Anderson taking 8 percent of the vote. He ended up beating Carter by 10 points and winning 44 states.

Romney has won white voters by the same 20-point margin, 59 percent to 39 percent. But the big difference is that in 1980, whites were 88 percent of the electorate, whereas in this election, they were just 73 percent.

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Black voters represented 10 percent of the electorate in 1980, and Carter won 83 percent of them. This year, black voters were 13 percent of the electorate, and went 93 percent for Obama.

But the big leap was among Hispanic voters, who jumped from 2 percent of the population in 1980 to 10 percent in 2008. And Romney is only winning 30 percent of Hispanics.