Democrats retain a slight edge nationwide as Americans head to the polls on Election Day.

In the final Hill.TV American Barometer poll before Tuesday's midterms, Democrats hold a six-point advantage on the generic congressional ballot.

In the survey, which was conducted among 1,000 registered voters by the HarrisX polling company, 43 percent of respondents said they would vote for the Democrat running in their U.S. House district while 37 percent said they would pick the local Republican.

Democrats have consistently led Republicans in Hill.TV surveys in recent months, thanks in part to discontent among their voters about President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE and his policies.

"Donald Trump is really the main issue of this election. It's him and his vision for what America should be," Mallory Newall, research director at Ipsos Public Affairs, said on Monday's broadcast of "What America's Thinking," Hill.TV's show about public opinion and the polling industry. "On this Democratic side, you have outrage about him, about, perhaps, the Supreme Court hearings and about health care."

Facing high enthusiasm from Democratic voters, President Trump has been ramping up his rhetoric about immigration as a means of trying to rally his supporters to turn out and vote.

"Immigration is the top issue among Republicans, and that's been the case in our Ipsos-Reuters polling for months," Newall said. "So you see the president talking about immigration, talking about this caravan marching toward the border to try and sort of manufacture some of that outrage and kind of gin up his base to turn out tomorrow."

The latest American Barometer survey was conducted online Nov. 2 and 3 and has a sampling margin of error of plus or minus 3.1 percentage points.

—Matthew Sheffield