Nate Silver: African-American Vote Is This Election’s X-Factor

— -- FiveThirtyEight's Nate Silver said that there may be an X-factor in this year's election results -- the African-American vote.

Silver made the comments to ABC News' Jonathan Karl and Rick Klein on the “Powerhouse Politics” podcast today -- the eve of Election Day.

FiveThirtyEight predicts a 69.4 percent chance of a Hillary Clinton win on Tuesday (and 30.6 percent for Trump) and predict that Clinton will garner around 300 electoral votes.

Of those electoral votes, there are still uncertainties, even for the best pollsters. If he could choose one demographic as an “X-factor” in this election, Silver said he’d pick the African-American population.

“The winning coalition Democrats need to win Michigan and Pennsylvania, and certainly Ohio, depends on very high black turnout along with winning some union, working-class white voters,” he said.

While voter turnout for several minorities is often a tossup, many of those groups, like Hispanic populations (concentrated in California and Texas), don’t affect swing states.

The African-American vote, on the other hand, could shape the Tuesday turnout for several states.

“You don’t see the kind of monumental turnout [in African-American voters] you had for Obama, and then that’s how Clinton could lose a Pennsylvania or a Michigan,” said Silver.