WASHINGTON — Hillary Clinton and her Democratic allies, unnerved by the tightening presidential race, are making a major push to dissuade disaffected voters from backing third-party candidates, and pouring more energy into Rust Belt states, where Donald J. Trump is gaining ground.
With Mrs. Clinton enduring one of the rockiest stretches of her second bid for the presidency, her campaign and affiliated Democratic groups are shifting their focus to those voters, many of them millennials, who recoil at Mr. Trump, her Republican opponent, but now favor the Libertarian nominee, Gary Johnson, or the Green Party candidate, Jill Stein.
While still optimistic that the race will turn decisively back in Mrs. Clinton’s favor after the debates, leading Democrats have been alarmed by the drift of young voters toward the third-party candidates.
The principal “super PAC” supporting Mrs. Clinton’s candidacy, Priorities USA Action, has concluded from its polling and other research that the reluctance to embrace the Democratic nominee among those who intensely dislike Mr. Trump is not going away and must be confronted.
“We’ll be launching a multimillion-dollar digital campaign that talks about what’s at stake and how a vote for a third-party candidate is a vote for Donald Trump, who is against everything these voters stand for,” said Justin Barasky, a strategist for Priorities USA.