–The Trump factor. These Senate candidates are trying to figure out what it would mean to run for re-election in a party whose presidential nominee, with the face and voice that would dominate national attention, would be Donald Trump.

The issue arises, of course because of the stratospheric levels of negative feelings toward Mr. Trump nationwide. In the new WSJ/NBC News poll, 65% of voters said they had negative feelings toward Mr. Trump. That includes 79% of Latinos and 75% of younger voters aged 18 through 34, two audiences where the GOP had been hoping to improve over its performance four years ago.

The question for GOP Senate candidates is whether such negative feelings could pull down other Republicans with spots down the ballot. It’s a complicated question because Mr. Trump might at the same time draw out to the polls, to the benefit of Republicans, more white working-class voters, many of whom see him as something of a potential savior.

Indeed, while 65% of all those surveyed said they had negative feelings toward Mr. Trump, that number falls to 51% among whites with less than a college education. Those working-class white voters might be particularly beneficial to Sens. Rob Portman of Ohio and Ron Johnson of Wisconsin as they seek re-election in states where working-class white voters are numerous.