With early voting for the U.S. presidential election in November already underway in some states, Republican presidential candidate Donald Trump and Democratic presidential candidate Hillary Clinton are ramping up their efforts to mobilize voters.

On Wednesday, Clinton travelled with Vermont Sen. Bernie Sanders to the University of New Hampshire in Durham, N.H., to court a crucial segment of the voting population – millennials. Clinton promoted her college affordability plan and encouraged young Americans to engage in this year’s election.

“None of that will happen if you don’t turn out and vote,†Clinton declared.

Allegra Chapman, the director of voting and elections at Common Cause, a non-partisan lobbying organization, told Â鶹´«Ã½ Channel on Thursday that votes from millennials, aged 18 to 34, could be crucial in the presidential vote.

“Younger voters are the largest voting block out there,†Chapman said. “They’ve overtaken baby boomers as the largest representative group and they really hold a lot of power in this election.â€

According to the , there are now 75.4 million millennials compared to 74.9 million baby boomers (aged 51 to 69) in America.

Chapman suggested that younger voter turnout is always a concern, but if all the eligible, younger voters show up at the ballot box, they could to turn the tide of this election.

She said that millennials have been very effective in voicing their interests in movements such as Black Lives Matter, Occupy Wall Street and DREAMers, a group advocating for immigration rights.

“What we need to do now is to help translate that kind of civic mobility into political action,†Chapman said.

Chapman said that her organization has noticed that many young Americans have been moving away from the two major parties and identifying as independents. In a recent , a third of voters aged 18 to 29 said they would vote for third-party candidates Gary Johnson, the Libertarian candidate or Jill Stein, the Green Party candidate. Chapman thinks this is why it’s imperative for Clinton and Trump to focus on millennials and listen to what they want.

“If candidates are doing that, then younger people are going to be more motivated to show up and vote,†she said.

First Lady Michelle Obama has been doing her part to draw attention away from independent candidates on behalf of Clinton. She warned students against voting for third-party candidates as she toured college campuses in Philadelphia and Pittsburgh on Wednesday.

“If you vote for someone other than Hillary, or if you don’t vote at all,†she said, “then you are helping to elect Hillary’s opponent (Trump).â€

Chapman said, only time will tell if Trump will follow Clinton’s lead on courting the millennial vote in the upcoming five weeks before the election. She believes that it’s up to young Americans to decide for themselves to act on their concerns and not just publicly voice them during demonstrations.

“They’re really going to need to show up and participate and vote,†Chapman said.

With files from The Associated Press