As Hillary Clinton and Donald Trump prepare to ramp up spending in the post-Labor Day sprint to Election Day, their fundraising stops in the Hamptons this summer — a longtime rite of passage for presidential hopefuls — has provided a glimpse into their distinct fundraising operations.

Clinton’s fundraising machine — fine-tuned over the course of two U.S. Senate campaigns and her failed 2008 presidential bid — cranked out nine events in a three-day swing through Long Island’s East End, and raised an estimated $20 million for the Democratic presidential nominee.

Trump, a real estate mogul staging his first political campaign, headlined two Hamptons events in July and August, which campaign surrogates said raised about $3 million.

Meena Bose, director of Hofstra University’s Peter S. Kalikow Center for the Study of the American Presidency said the Hamptons fundraising efforts provided a study in contrasts between Clinton’s “very tightly organized operation” and Trump’s upstart campaign.

“The Clinton campaign’s fundraising is well structured,” Bose said. “The campaign has clear goals and plans to get there. The Trump campaign, in contrast . . . is consciously not following the traditional structure. What that means as far as fundraising and political support remains to be seen.”

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Nationally, Clinton has outpaced Trump in fundraising, according to federal campaign finance records, which show her campaign pulled in $90 million to Trump’s $80 million in July.

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Clinton and the Democratic Party have used that money to open nearly 291 field offices in battleground states, compared to 88 offices that have been opened by Trump and Republicans. Clinton also outspent Trump in television advertising, having spent $45 million in ad buys as of July, compared with Trump, who spent $2.8 million on ads, according to data compiled by NBC News.

Doug Muzzio, a political science professor at Baruch College, said while Trump has repeatedly said he would self-fund his campaign to avoid being beholden to big-donors, it was a “mistake” for Trump not to invest more time on fundraising events, especially on the East End.

“It’s not only a question of money, it’s a question of publicity in the largest media market in the country,” Muzzio said. “The fact that he’s not doing more is not inconsequential . . . It’s not just about raising money for your campaign, but also helping down ballot races.”

Clinton three-day fundraising blitz between Sunday and Tuesday included large-scale events such as a “Garden Party” that drew 200 supporters who paid anywhere from $2,700 to $33,400, to more intimate receptions, such a gathering hosted real estate developer Jeff Blau and his wife, Lisa, at their Wainscott home for 20 supporters, who each paid $33,400 for the chance to meet Clinton.

Nassau Democratic Committee Chairman Jay Jacobs, a longtime Clinton fundraiser, who serves on the campaign’s national finance committee, said that while Republican and Democratic presidential candidates have headed to the Hamptons to raise millions in a short-amount of time, he could not recall another recent presidential candidate who held as many consecutive fundraisers as Clinton did this week.

Suffolk County Republican Chairman John Jay LaValle, a Trump campaign surrogate, said Trump is less focused on raising money from wealthy donors and more concerned with reaching voters through his large-scale rallies.

“Money is not going to win this race,” LaValle said. “Donald Trump is raising small money, from everyday Americans and matching it with his own money. That’s the stark contrast; he is not an establishment candidate.”