Clinton faces an increasingly tight race against Trump and may need to better energize young voters to beat him, as older voters typically lean Republican. Recent polls suggest she lags well behind President Barack Obama's support from young voters in 2008 and 2012.
A Quinnipiac poll last week showed Clinton capturing only 31 percent of voters 18-to-34 years old, leading Trump by only five points. Her support fell from 48 percent in August, when she had a 24-point advantage over Trump. Some young voters have turned to either the Green Party's Jill Stein or the Libertarian Party's Gary Johnson amid concerns about Clinton's integrity and commitment to progressive policies.
Obama captured 60 percent of voters under 30 in 2012. Clinton will need young voters to turn out in cities like Philadelphia and Pittsburgh to win swing state Pennsylvania, where rural areas vote largely Republican.
"Even if you're totally opposed to Donald Trump, you may have some questions about me. I get that. ... I will never be the showman my opponent is. And you know what, that's OK with me. I do spend a lot of time on the details of policy," Clinton said.
Obama and others have tried to mobilize voters for Clinton recently as the race tightened. Obama said this weekend that he would consider it a "personal insult" to his legacy if black voters did not turn out for Clinton. Clinton's primary opponent Bernie Sanders, a popular figure among young voters, has also contended that this election is not the time to vote for a third-party candidate.
Clinton on Monday outlined her own policies that appeal to millennials, like making public college more affordable, reducing racism in policing and sentencing and fighting climate change and pushing for renewable energy. She tried to contrast herself from Trump, highlighting his push for more fossil fuel production and his years-long "birther" campaign against Obama, which he relented on only last week.
In particular, she stressed how close the race had become.
Said Clinton: "Not voting is not an option. That just plays into Trump's hands, it really does."