Boston 2024 released this video as part of its campaign to help bring the 2024 Summer Olympics to Boston, Mass. (YouTube/Boston 2024)

It was a daunting task from the beginning, trying to convince leaders of the U.S. and international Olympic movements that Washington, with its attendant symbolism of American strength and political ambition, would be a wonderful setting for a Summer Games. And in the end, it may have been that very association that torpedoed the city’s chances of securing the 2024 Games.

On Thursday, the U.S. Olympic Committee chose Boston over three other finalists — Washington, Los Angeles and San Francisco — as the city it would submit to the International Olympic Committee as the American candidate for 2024.

“This bid uniquely combines an exciting, athlete-focused concept for hosting the Olympic and Paralympic Games with Boston’s existing long-term vision,” USOC CEO Scott Blackmun said in a statement. “We look forward to working with Mayor [Marty] Walsh and the Boston 2024 team to fully engage with the local community and identify ways we can make the bid even better.”

The selection was a mild upset. The front-runner seemed to be Los Angeles, site of the 1932 and 1984 Games and the city seen as being closest to Olympics-ready.

For the organizers behind Washington’s upstart bid, Thursday’s decision marked the end of a nearly two-year effort, during which local businessman Russ Ramsey and Washington Capitals and Wizards owner Ted Leonsis — the group’s chairman and vice chairman, respectively — worked to marshal support among business leaders, politicians and community groups.

“It was an honor to work with dozens of leaders from across the Capitol Region to envision how the Olympic Games would advance the goals of this community and foster greater unity,” Ramsey said in a statement. “I grew up in this city and have seen firsthand how sport can be a force for good and how incredibly impactful it can be on a young person’s life. I remain deeply hopeful that the Olympic Games will return to the U.S. in 2024 and remain committed to working with the leaders of this region to ensure opportunities for our youth to pursue Olympic dreams.”

Phil Mendelson, the D.C. Council chairman, said it was important to “understand why Boston was perceived as better.”

“There's no question it was disappointing,” Mendelson said. “. . . It would have been a catalyst for housing and economic activity. If we had done it right, it would have been very profitable, not just for the District but for the region.”

The Washington group announced its intentions to bid on the Games in August 2013 and unveiled its board, logo, Web site and slogan (“Unity”) in September 2014. Although plenty of citizens did the usual amount of grousing about an unwanted influx of visitors, the group’s efforts proceeded with almost no formal opposition until this week, when a group calling itself No Olympics DC rolled out a Twitter campaign against the Games.

Organizers of D.C.’s bid proposed a compact Games focused largely around venues in the District and inner suburbs — as opposed to the city’s failed 2012 bid, which envisioned a slew of events from Baltimore to Richmond.

With economic development serving as a guiding principal — and argument — for hosting the Games, Washington’s bid focused on building those new facilities along the Anacostia River in the eastern part of D.C., which includes some of the poorest neighborhoods in the region.

London had success using the 2012 Olympics as the pretext for rebuilding its East End; maybe D.C. could do the same for neighborhoods along the Anacostia River.

DC 2024 released this video as part of its campaign to help bring the 2024 Summer Olympics to Washington, D.C. (DC 2024)

Thus the organizers plotted an Olympic Stadium to replace RFK Stadium, where Redskins owner Dan Snyder already was eyeing a new permanent facility, and an Olympic Village next door, where D.C. officials were already plotting a mixed-use neighborhood.

They proposed a new tennis facility east of the Anacostia River and began vetting a series of locations in Prince George's County for events.

The University of Maryland could host gymnastics at Xfinity Center. National Harbor could host weightlifting, table tennis, badminton or handball.

FedEx Field could even serve as the Olympic Stadium in case the RFK site didn’t work.

Although Washington’s bid leaders got positive feedback on their presentation from the USOC board, the city was always considered an underdog among Olympics insiders, mostly because of its position as the seat of American power. After a series of recent failed bids, the USOC was determined to pick a candidate that could win over the IOC, a body that is widely assumed to include pockets of anti-Americanism.

The U.S. hasn’t hosted a Summer Olympics since the 1996 Games in Atlanta, an unusually long time for the IOC’s biggest broadcast partner.

After submitting losing bids for New York in 2012 and Chicago in 2016, the USOC declined to bid on the 2020 Games.

In its statement Thursday, the USOC said the selection of Boston came after “more than one round” of voting by the 15-member board, which met privately at Denver International Airport. The final vote, the statement said, was unanimous.

Ramsey and Leonsis, awaiting the decision at the Washington 2024 offices on Pennsylvania Avenue in Northwest, took the call from the USOC just after 6:30 p.m. They were not given any specific feedback. Both declined to comment beyond the statement the group released Thursday night.

Boston represents a new tack for the USOC — an old, storied East Coast city known for its universities and sports fanaticism. Besides Los Angeles and Atlanta, only one other U.S. city has hosted a Summer Games: St. Louis in 1904.

“This selection is in recognition of our city’s talent, diversity and global leadership,” Walsh said in a statement. “Our goal is to host Olympic and Paralympic Games that are innovative, walkable and hospitable to all. Boston hopes to welcome the world’s greatest athletes to one of the world’s great cities.”

Aaron Davis, Mike DeBonis and Jonathan O’Connell contributed to this report.