When it comes to presidential campaigns, the question “are you too old?” is nothing new.

In the election of 1840, 67-year-old Whig candidate William Henry Harrison was attacked by the Democratic press as “granny” and “General Mum” over his “age and imbecility.”  When he was sworn in after defeating incumbent President Martin Van Buren, Harrison was 68 — the oldest person ever elected president until Ronald Reagan (age 69) broke his record 140 years later.

When Reagan ran for re-election, Democrats tried to make his age an issue, too. Reagan brushed it aside when he pledged during a debate with Democrat Walter Mondale “not to exploit, for political purposes, my opponent’s youth and inexperience.”

With the oldest president running for re-election in American history (Trump will be 73 on Friday) against a Democratic field whose 76-year-old front-runner is the third-oldest candidate in the race, it’s hardly a surprise that age is an issue.  (Sen. Bernie Sanders is 77 and former Alaska Sen. Mike Gravel–who FiveThirtyEight.com just qualified as a “major candidate” –is a spry 89)

And with 24 candidates in the field, including four who would be the youngest president ever if elected (Buttigieg, Gabbard, Moulton and Swalwell), it’s no surprise that they’re playing the age card.

Beto O’Rourke told MSNBC’s Morning Joe “You cannot go back to the end of the Obama administration and think that’s good enough.” When asked if he believes Biden is a “return to the past,” O’Rourke answered, “He is and that cannot be who we are going forward.”

“I think our party is certainly ready to lift up leaders from a new generation,” Pete Buttigieg told the Today show. “I think this race will create a fair playing field where people who’ve been in the public sphere for longer than I’ve been alive and people like me get to compete on the basis of our ideas.”

“Longer than I’ve been alive” is hardly a subtle commentary on the age gap.

And yet, as evidenced by the examples above, it’s possible to be at the edge of the age bell curve and still be elected. (In 1840, the average life expectancy was around 40 years old.) Do voters — particularly in New Hampshire– care about the candidate’s age? Do Democrats think Joe Biden is just too old?

On one hand, an April poll of Granite State voters by Suffolk University found 73 percent of Democrats thought “a person 70 years old or older” is not too old to run for president.   On the other hand, when Emerson University asked New Hampshire Democrats to identify the ideal age of a presidential candidate, 71 percent preferred a president in their 50’s or 60’s. Only 9 percent said their 70’s, and just 2 percent said in their 80’s.

And in a new YouGov national poll, most Democrats say 75 is too old to be president, while 51 percent say being 80 would “make it too difficult to do the work required of a U.S. President.”

If elected, President Biden would turn 80 just after the 2022 midterm election.

“Age is a difficult issue for candidates to use because by raising it, they run the risk of alienating the highest propensity voters: older folks,” Emerson’s director of polling Spencer Kimball told NHJournal. “And if the nominee is one of the senior Democrats, the point is moot because President Trump is a contemporary.”

In a sign of how American politics is changing in a myriad of ways, Americans are now more likely to say they would reject a candidate for being too old (70+) than for being gay, according to a new Reuters/Ipsos poll.

Interestingly, the age question is dogging the Biden campaign far more than Bernie Sanders, despite the  Vermont senator being a year older.

“People have a right to question all of our ages,” Biden said on Tuesday. “It’s a totally legitimate thing. All I can say is watch me.”

People are watching. What they’re seeing is a significant difference in energy levels between Bernie and Biden on the stump. “For some reason, age hasn’t been much of an issue with Bernie Sanders,” notes liberal Washington Post columnist Paul Waldman. “Perhaps it’s because he looked 77 even when he was in his 40s and hasn’t changed a bit in the time since.”

During his most recent visit to the Granite State, Sanders appeared at seven events in less than 48 hours. His deputy N.H. state director Carli Stevenson tells NHJournal, “He’s got a young staff, and he keeps the rest of us playing catch up. Bernie Sanders doesn’t slow down.”

This stands in stark contrast to the Biden campaign pace, which has been compared to the “French work week” schedule. “It’s the 78-year-old elephant in the room,” Democratic consultant Fernand Amandi told Politico.

“I’ve had conversations with people who think Biden and Sanders are too old, and others who don’t think it’s an issue,” longtime NH Democratic activist Judy Reardon told NHJournal.  “I’m a baby boomer and I’m sick of baby boomer presidents. And Biden and Sanders are pre-baby boom.

“All things being equal, my preference is to vote for someone younger than I am.”