And in August 2015, Bernie Sanders began to loosen Hillary Clinton’s grip on New Hampshire by speaking to the party’s youthful left — around the same time Donald Trump addressed 2,500 at a raucous rally in Derry and helped legitimize his candidacy.

It was late summer 1999 when John McCain skipped Iowa to hop on his “Straight Talk Express” campaign bus in New Hampshire, where he eventually won the primary. Four years later, Howard Dean demonstrated his appeal through large-scale events in the early states.

Historically, the weeks before Labor Day have been among the most interesting in the presidential primaries, as candidates decamp from Washington to Iowa and New Hampshire to campaign. As a result, the race often resets in a fundamental way.


But in the 2020 Democratic campaign for president, those kinds of shifts are unlikely to happen next month.

Instead of campaigning intensely in the early voting states — shaking hands on Hampton Beach or eating pork on a stick at the Iowa State Fair — most Democrats running for president are much more focused on meeting the Democratic National Committee’s rules for making the cut for the third national televised debate.

(The lineup for the second set of debates, which will be held on Tuesday and Wednesday, has already been set.)

To make the September debate stage in Houston, candidates must have at least 130,000 unique donors to their campaigns and receive at least 2 percent in four polls that the DNC deems credible.

So far, just eight have said they will qualify: former vice president Joe Biden; Senator Cory Booker of New Jersey; South Bend, Ind., Mayor Pete Buttigieg; Senator Kamala Harris of California; former Texas representative Beto O’Rourke; Senator Bernie Sanders of Vermont; Senator Elizabeth Warren of Massachusetts; and New York entrepreneur Andrew Yang.


Everyone else must find a way to meet the two qualifications by the Aug. 28 deadline. For some candidates, that means flying to Los Angeles and New York to get on as many television programs and podcasts as they can. For others, it means spending their remaining money on social media campaigns aimed at improving name recognition and getting new donors.

Cory Booker, left, was in Manchester, N.H., on July 13. Associated Press/FR62846 AP via AP

It probably does not mean going to early states on the nominating calendar, including Iowa and New Hampshire, unless they are somehow guaranteed there will be national news coverage of their trips. After all, the pollsters who run the two New Hampshire surveys the DNC uses in its determination — the University of New Hampshire and Monmouth University — both tell the Globe they are not planning to release another poll before the Aug. 28 deadline. (Monmouth pollster Patrick Murray said he will do an Iowa poll next month.)

“Without a poll to help them make the debate, there really is no reason to come to New Hampshire unless you have already qualified,” acknowledged UNH pollster Andy Smith.

And so far they are not coming. There are currently 25 candidates running for president. During the 26-day period that began last week, only two candidates had or were scheduled to have events in the state. Warren showed up Saturday for a pair of events. And on Aug. 1, author Marianne Williamson will spend a single day in the state.

“The formula for how to run for president has changed specifically because of the debate qualification hurdles,” said Democratic strategist Colin Strother. “It gives the front-runners an even greater advantage as they will be able to really zone in and protect their market share while the folks at the bottom are just trying to get noticed.”


In New Hampshire, without candidates visiting the state for weeks or months, campaign staff are forced to get creative to engage voters who expect attention every four years.

Booker’s campaign is inviting supporters and activists to movie nights to watch “Street Fight,” a documentary about Booker’s first campaign for mayor of Newark. They are also inviting supporters to “gardening mornings” with staff.

O’Rourke’s staff and volunteers hosted a cleanup at Wallis Sands State Beach in Rye last Sunday. Senator Amy Klobuchar called into three rural radio stations in the state while she was in Washington, D.C.

The Sanders campaign held volunteer workshops around the state, and Buttigieg’s campaign is handing out invites to bowling and poetry nights. (A hiking trip in the North Country is also in the works.)

“This is a campaign built around joy and community and fun,” said Buttigieg’s New Hampshire director, Michael Ceraso.

Pete Buttigieg campaigned at the Revolution Taproom & Grill in Rochester, N.H., on July 12. Associated Press

Even events devised to lure presidential candidates to New Hampshire aren’t necessarily working this season. The Hollis Democrats — among the most active party committees in the state — recently attempted to hold a presidential candidate night at a historic barn, but no candidate showed.

On Thursday night, roughly 60 people showed up for the Somersworth Democrats’ BBQ, but only two presidential campaigns were willing to pay the $250 fee for a staffer to speak for five minutes: Yang and former housing secretary Julian Castro.


One Democrat who is far from qualifying for the September debate is Representative Seth Moulton, of Salem. His staff says he plans to spend “significant” time in New Hampshire in August.

“Other campaigns are making strategic decisions solely based on getting on a debate stage, while we are strategically focused on winning over primary voters,” said Moulton’s campaign spokesman, Matt Corridoni.

Campaign staffs and strategists argue the Iowa caucuses and the New Hampshire primary will still play a huge role in selecting the nominee. The Iowa caucuses are scheduled for Feb. 3, and the New Hampshire primary is expected to be held eight days later.

But until then, the DNC debate rules have prompted a shift in campaign strategy for nearly every candidate in the field.

“I have always said the threat to the New Hampshire primary isn’t some state that wants to jump ahead, but when the candidates stop showing up,” said Smith, who also teaches a presidential primary class at the University of New Hampshire. “And in this pivotal period, they aren’t showing up for very logical reasons because of the DNC rules. This is concerning to see for people who value the New Hampshire primary, but they will be back soon.”

James Pindell can be reached at james.pindell@globe.com. Subscribe to his Ground Game newsletter: http://pages.email. bostonglobe.com/GroundGameSignUp.