WASHINGTON, June 22 — Cool it, Generation X. Slow your roll, Millennials.

Senator Elizabeth Warren turns 70 on Saturday, meaning the three top-polling Democrats seeking their party’s 2020 presidential nomination — not to mention President Donald Trump himself — are septuagenarians who could become the oldest commander in chief ever elected to a first term.

Members of the club include frontrunner Joe Biden, the former vice president who is 76, and liberal Senator Bernie Sanders, 77.

Trump at 73 is already the nation’s oldest leader, and he’s running for re-election to keep it that way.

Age has the potential to emerge as a liability in the 2020 presidential race: while calls for generational change and new vision have rarely been louder from the Democratic ranks, the leading candidates have never been older.

They may be flying in the face of what Democrats want.

"They’re all too old,” South Carolina attorney and former gubernatorial candidate Marguerite Willis told AFP Friday at a meet-and-greet for presidential hopeful Kamala Harris in Columbia.

"I have standing to say this,” the 69-year-old added. "I know that it’s time for us to pass the baton.”

Willis said she will vote for Harris, who at 54 is "just right” in terms of age and experience.

Many other Democrats seem to agree on the need for a younger candidate.

Recent polls show the party’s voters are eager for a dynamic, energetic leader who can relate to young Americans and cast an eye to the future, not an entrenched politician who lingers in the past, as Biden is known to do.

A Pew Research Centre poll last month found just three per cent of Democrats say they believe the best presidential age is 70 or above, while the bulk — 47 per cent — say the ideal age is in their 50s.

That fits with American custom. The median age for the country’s 45 presidents has been 55, and only 10 of them have been over 60 on their first day in office.

In a further sign that age does matter, 48 per cent of respondents to a Reuters/Ipsos poll this month said they were "much” or "somewhat” less likely to support someone for president if the person was older than 70.

That might be worrisome for the senior citizens in the race, and offer hope for the 17 Democratic candidates who are under 60.

Candidate Pete Buttigieg, the South Bend, Indiana mayor who at 37 is less than half Biden’s age, often speaks of the country needing "a new generation of leadership” culturally in tune with young people and the challenges they face, like college affordability, workplace automation and climate change.

Democratic 2020 US presidential candidate and US Senator Elizabeth Warren at the Manchester Democratic City Committee Flag Day Dinner in Manchester, New Hampshire June 14, 2019. — Reuters pic

Out of step?

The age issue bubbled up recently thanks to two moves by Biden, whose mainstream blue-collar appeal could make him a formidable opponent to Trump.

After decades of support for a conservative measure that prohibits federal funding for almost all abortions, he awkwardly flipped at the first sign of pressure on the campaign trail, announcing he could no longer back a law that hurts low-income women.

Then he caused a firestorm when he expressed a longing for the "civility” that existed between him and two avowed segregationists in the US Senate, which he joined in 1973.

The comments, during a New York fundraiser, marked another sign that "Uncle Joe” was out step with the progressive, younger, more diverse contingent in the party.

Sanders, while older than Biden, has not generated the same level of debate about his age, perhaps because he has kept up a notably busier campaign schedule.

Trump has seized on the concern, deriding Biden as a "mentally weak” candidate being out-hustled by rivals.

"He looks different than he used to, he acts different than he used to, he’s even slower than he used to be,” Trump told reporters.

Trump isn’t the only one questioning Biden’s age, which will be 78 on Inauguration Day.

"It’s the 78-year-old elephant in the room,” consultant and pollster Fernand Amandi, who consulted for the Obama-Biden campaigns in 2008 and 2012, told Politico earlier this month.

While Biden himself has acknowledged that queries about age are fair game, it was Ronald Reagan, running for re-election at 73, who famously used humour to devastating effect to dispel the concerns.

Asked at a 1984 debate with Democrat Walter Mondale whether he was confident he could keep a gruelling schedule at his age, Reagan said "I am not going to exploit, for political purposes, my opponent’s youth and inexperience.” — AFP