Hillary Clinton's campaign is confronting an emerging risk to her presidential ambitions — if Donald Trump continues to trail her in opinion polls many Democrats may simply stay at home on Election Day.
Without enough popular support, Clinton would enter the White House lacking the political capital she would need to drive through her agenda. In the worst-case scenario it could cost her the presidency if Republicans turn out in big numbers on Nov. 8.
Clinton, the Democratic nominee, has spent much of her campaign sounding the alarm over the prospect of a President Trump. She has struggled to lay out a compelling vision for her presidency and has failed to excite key constituencies, including millennials, minority voters and liberal Democrats.
Opinion polls show that many voters are backing Clinton primarily to stop Trump, the Republican nominee, from getting into the White House. If they believe he has no hope of winning, then what would their motivation be to turn up at the polls?
In a recent Reuters/Ipsos poll about half of all Clinton supporters said they were backing her to keep Trump from winning. By contrast, just 36.5 percent said it was because of Clinton's policies and just 12.6 percent said it was because they like her personally.
"Turnout is correlated with levels of competition," said Michael McDonald, an elections expert at the University of Florida. "The higher the competition, the higher the turnout."
The young Americans, blacks, Latinos, and low-income voters who make up much of the Democratic base often need to feel motivated by a particular candidate or issue to turn out, McDonald said, as was the case with President Barack Obama's candidacy in 2008.
Clinton's campaign has long worried about voter complacency and has at every turn pushed the notion that the race is close and that Trump is unfit to be president. With her lead growing, that task grows more difficult.