The presidential candidates have been unable to attract a groundswell from 18- to 29-year-old voters like the one that helped push President Barack Obama to wins in two elections.

That voting bloc could provide critical mass for a win, particularly since they and the previous generation, the Generation Xers, now outnumber baby boomers and their parents, who have dominated the economy and elections for decades.

Donald Trump and Hillary Clinton need to reach younger voters, said Audrey Haynes, a political science professor at the University of Georgia, but so far they are failing.

“This is going to be a mobilization election. Will Clinton be able to get those Bernie (Sanders) supporters to really show up and vote? Will those young people at Trump rallies really vote for him?” said Haynes. “It’s a big question mark.”

As of July, about 126 million Millennial and Gen X adults were eligible to vote, compared to 98 million boomers and those who are older, according to a Pew Research Center analysis of census data.

In the run-up to the primary election, Sanders’ liberal platform, including free college and social justice, appealed to young voters; as did Republican candidate Marco Rubio’s youthfulness and similar circumstances. Like many of them, he struggled to pay off student loans.

Clinton does hold a lead among younger voters, about 41 percent versus 20 percent for Trump in national polls. But that's far from the backing President Obama had from that age group when he won at least 60 percent of the under-30 vote in both the 2008 and 2012 elections, according to American National Election Studies.

Clinton and Trump, 68 and 70 years old, “are senior citizens,” said Marilyn Davis, a political science professor at Spelman College. Younger voters felt Sanders was “fresh, and was a candidate who was about issues they cared about,” Davis said. But with the two current candidates, “There is no issue agenda, there is pretty much attack and counterattack and suspicion,” Davis said. “That’s not going to work anymore.”

In an August AJC poll, among Georgia voters age 18-39, Clinton led Trump 44 percent to 29 percent. Libertarian Party candidate Gary Johnson polled at 21 percent — very high compared to the number of votes third-party candidates typically get in the election. Jill Stein, Green Party candidate, got 4 percent.

But despite Clinton’s lead over Trump, 61 percent of those voters had an unfavorable view of her. Trump’s unfavorable rating was even worse, 70 percent.

Talk to young voters — including those who typically lean Democratic — and questions emerge about Clinton’s ethics.

Samantha Ramirez, 26, knows she will vote in November, but doesn’t yet know for whom. Both major-party candidates have more cons than pros, said the former Sanders supporter. When Sanders was eliminated, Ramirez was hesitant to support Clinton.

“I’m concerned about her trustworthiness,” she said. “Those emails (official communications housed on Clinton’s private server when she was Secretary of State) were red flags and made me wonder, am I dealing with a liar?”

Members of Georgia State University’s Panthers for Bernie Sanders couldn’t come to a consensus on whether to support Clinton, and decided not to officially support any presidential candidate.

“When Bernie Sanders said something you knew you could believe it, but with Hillary Clinton you feel like she says one thing to coal miners in West Virginia and something else to another group in another place,” said Nick Langley, 28, a Georgia State University graduate student and leader of the group.

“Both of them sometimes do things that seem unpresidential,” said Georgia State University student Alora Pruitt, 18. “She tries too hard to appeal to younger voters, like her Snapchatting. It’s too much. It’s almost pandering.”

Nationally, Republican groups at Harvard, Penn State, Princeton and the University of Connecticut are not endorsing Trump, and groups at other colleges are still considering their endorsement or are divided on their support.

The young voter group is racially and ethically diverse. About 17 percent are Latino; 15 percent are black; about 5 percent were born outside the United States; and 21 percent have a parent born outside the country, according to the Center for Information and Research on Civic Learning and Engagement research group at Tufts University.

For many of them, issues like immigration are important, and talk of “building walls” can be a turnoff.

“This election has become a joke, with Clinton’s emails and Trump wanting to kick everyone out of the country,” said Pilar Valdez, 21, who has several family members dealing with immigration issues. The candidates’ “immigration reforms will be the deciding factor for me come November,” she said.

Anthony Braswell plans to “hold his nose” and vote for Trump. The self-described conservative Christian supported Texas Sen. Ted Cruz and his platform of states’rights and small government in the presidential primary. “I don’t necessarily agree with his (Trump’s) aggressive tactics, but his values align more closely with mine than Hillary” said Braswell, 38, an engineering student at Georgia State University-Perimeter College.

The college Republican group at the University of Georgia — the largest in the nation with more than 500 members — is supporting Trump, but its leader notes there are many different views in the group. Georgia Tech’s Republican group is not endorsing any candidates. Many of the college political groups in Georgia are choosing instead to focus on local elections.

“Millennials are smart and they know how to get information. They may take a lot of selfies and Snapchat way too much, but they’re smart, and they don’t like made-up problems and are resistant to propaganda,” said Haynes, the UGA political science professor. And unlike Obama — or even Sanders and Rubio — Clinton and Trump don’t seem to have the same connection with young people.

“It’s hope and change versus, this is hopeless and we need change.”