Gingrich: Every American Has a 'Moral Obligation' to Vote

Eric Trump: 'This Is a Movement to Take Back Our Country From Career Politicians'

Krauthammer: 'Civil War' in the Republican Party Is About to Begin

UPDATE, 10:25pm ET: Fox News Channel has now called Ohio for Donald Trump. 

UPDATE, 9:45pm ET: Bill Hemmer updated the Ohio returns moments ago as the Buckeye State continues to trend red.

Watch above.

UPDATE, 7:50pm: The Clinton campaign is concerned about lower-than-expected turnout in Cuyahoga County, which includes Cleveland, Jennifer Griffin reported. The race in Ohio remains too close to call.

UPDATE, 7:30pm: Republican Sen. Rob Portman will win re-election, Fox News projects.

Karl Rove says he believes Ohio and North Carolina are likely to "keep us up late tonight."

The polls have closed in the swing state of Ohio, where 18 electoral votes are at stake.

The Buckeye State is seen as a must-win for Donald Trump in his bid for the White House.

Ohio voters have chosen the electoral vote winner in the last five presidential elections:

2012: Barack Obama
2008: Barack Obama
2004: George W. Bush
2000: George W. Bush
1996: Bill Clinton

The latest polling average has shown Trump with a three-point lead.

Stay with Fox News Insider for the latest results from the Decision Desk.

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