Yet the Libertarian Party’s presidential ticket — composed of former GOP Gov. Gary Johnson of New Mexico and former GOP Gov. Bill Weld of Massachusetts — appears to draw more from voters who might otherwise be aligned with Clinton, especially younger voters.

The same is true of Green Party nominee Jill Stein — though to a lesser degree, since Stein doesn’t earn nearly the same level of support as Johnson.

Here’s why Democrats should be concerned: As Trump’s support has dwindled in recent days — leaving the GOP nominee with just his fervent supporters — some soft voters might be moving into Clinton’s camp when asked on a two-way ballot, but defecting to a third candidate when given other options.

“Trump voters are mainly Trump voters, but Clinton voters are still not quite happy that they’re going to end up voting for her,” said Monmouth University pollster Patrick Murray, who has studied the role of third-party candidates in pre-election polls.