LACONIA, N.H. (AP) — Amy McInerney at first saw Joe Biden as Democrats’ best hope to beat President Donald Trump — an experienced politician with the potential to peel off some of Trump’s working-class supporters. Then she heard Pete Buttigieg speak.

“I felt like Pete more represented my generation,” said McInerney, 33, as she held her 6-month-old daughter, who sported a pink “Buttigieg 2020” onesie. “There need to be voices that are younger represented.”

Separated by 40 years, Biden and Buttigieg represent the generational poles of the crowded Democratic presidential primary. Biden, 76, would be the oldest person elected president. Buttigieg, the 37-year-old mayor of South Bend, Indiana, would be the youngest. Biden casts his decades of experience in Washington as a remedy for Trump’s turbulent tenure, while Buttigieg argues that the moment calls for the energy of a new generation.

“A lot of this is simply the idea that we need generational change, that we need more voices stepping up from a generation that has so much at stake in the decisions that are being made right now,” Buttigieg said shortly after announcing his candidacy.

At a time when the Democratic field is sorting out its differences on issues from health to immigration, that call for generational change, and how Democrats resolve it, could prove to be even more consequential. It’s a fight not just over which candidate gives Democrats the best chance of defeating Trump in 2020, but the direction of the party for years to come.

So far, Biden’s and Buttigieg’s strategies have yielded early success. Biden has led primary polls for much of the year, while Buttigieg tops the most recent fundraising race, amassing $24.8 million in second-quarter fundraising.

“The benefit of some of the older candidates is being able to show that experience,” said Tom Perriello, a former Democratic congressman from Virginia who was elected at age 33. “But newer candidates can sometimes run on the sense that they are more genuinely committed to change having not necessarily been part of the system that people feel has not delivered.”

Democratic voters have long been drawn to calls for generational change. President John F. Kennedy laid the predicate in his 1961 inaugural address when he said that “the torch has been passed to a new generation of Americans.” The last two Democrats to win the White House campaigned in part on the promise of a fresh start — Bill Clinton, whose 1992 win at age 46 made him the first baby boomer president, and Barack Obama, who swept to victory in 2008 at age 47 over 72-year-old John McCain. The 2018 midterms also ushered in a younger generation of Democratic lawmakers, including a historic number of women and minorities who were first-time candidates.

“The wait-your-turn approach to politics has never been particularly effective in Democratic politics,” said Ben LaBolt, a Democratic strategist who worked for Obama’s 2008 campaign.

But for some Democratic voters, the draw of a younger, less experienced candidate is tempered in 2020 by the risks of losing to Trump, a candidate many in the party view as an existential threat to democracy.

“I don’t think the mayor of South Bend should run for president in 2020 when the stakes are so high with Trump,” said Kate Bailey, a 30-year-old health care advocate from Hooksett, New Hampshire. “I would love to see the generational torch be passed. But honestly I don’t feel like this is the best time for a 37-year-old to run for president.”

Biden’s campaign had begun to subtly make a similar case.

“Vice President Biden believes the issues facing our country today aren’t generational challenges, they’re existential challenges,” said Kate Bedingfield, Biden’s deputy campaign manager.

Part of the allure for Democrats of a younger candidate has been the prospect of energizing younger voters. With Obama on the ballot in 2008, nearly 2 million more young people voted in the presidential election.

Yet Biden’s campaign also sees an opportunity to appeal to older Americans, who vote at higher rates. According to the Census Bureau’s Current Population Survey, 71% percent of those age 65 and over voted in the 2016 presidential election, as did 67% of those between the ages of 45-65. Just 46% of Americans under 30 voted.

While younger Democratic voters skew more liberal than older Democrats, the ideological lanes are more scrambled in the presidential campaign. Biden hews to the center, but two of the other oldest candidates in the race are also the most liberal: 77-year-old Bernie Sanders and 70-year-old Elizabeth Warren. During the 2016 Democratic primary, Sanders had broad support from young voters who were drawn to his plans to lower college costs and eliminate student debt.

“It’s not the age of the messenger, it’s the freshness the ideas,” Sanders adviser Jeff Weaver said in an interview with The Associated Press.

Buttigieg, meanwhile, shares some of Biden’s more moderate views.