Sidwell Friends School (Gerald Martineau/The Washington Post)

Sidwell Friends, the elite private school known for educating the children of presidents and members of Congress, has lent its support to a group of former students and faculty who are seeking to open a public charter school in the District.

The aspiring charter founders say they want One World Public Charter School to give middle-school students from across the city an opportunity to experience — for free — the caliber of education that costs $34,268 a year at the independent Quaker school.

Tom Farquhar, Sidwell’s head of school, spoke in favor of One World last week at a D.C. Public Charter School Board hearing. “These are extraordinary people,” Farquhar said, “and they have demonstrated in their lives prior to this an extraordinary commitment to the children of our community.”

Charters have drawn leaders from high-flying college-prep schools before: A graduate of National Cathedral School started the high-performing D.C. Prep charter network, while a Sidwell alumnus co-founded the SEED School, a charter boarding school.

But it’s unusual for a brand-name private school to publicly endorse a start-up charter and to agree, as Sidwell has, to explore opportunities for a continuing relationship. Should One World win approval next month to open its doors in fall 2014, a public vote of confidence from the school that educates President Obama’s daughters could give it an immediate competitive advantage in a crowded District school marketplace.

“Using an established institution in the city that everybody knows undoubtedly is a pretty effective way to connect with parents,” said Don Soifer, a member of the D.C. Public Charter School Board. “It’s a potential cachet that is definitely of value.”

Some critics say that the proposed charter could draw the most motivated students away from the city’s traditional schools, accelerating a trend that they say is hindering those traditional schools’ efforts to improve.

“I’m concerned about this move toward hypercompetition,” said Daniel del Pielago, an organizer at the community group Empower D.C., which opposes the expansion of charters. “It’s not ‘Let’s make our public school system, our community schools, a lot better.’ It’s ‘I’m going to get my kid into this one really high-performing school.’ ”

One World’s founders seek to have the school along 16th Street in Northwest, about three miles east of Sidwell and in a ward where the only traditional middle school, MacFarland, is slated to close in June because of low enrollment.

The school hopes to enroll 300 diverse students, including those living in poverty and those who could afford to pay full freight at Sidwell but would prefer a public school.

Students would take both Spanish- and Chinese-language classes. They’d have art classes nearly every afternoon for 90 minutes. To graduate from eighth grade, they’d complete a “passion project” — an independent investigation of a topic of their choice — and they’d have opportunities to travel abroad.

“The only difference between low-income kids and Sidwell kids is the exposure — exposure to arts, to music, to active dialogue, to questioning the world,” said Marta del Pilar Lynch, a One World co-founder who graduated from Sidwell in 1991. “That type of child can be cultivated whether you’re on Section 8 housing and getting food stamps or whether your family has $200,000.”

Democratizing access to a Sidwell-quality school is an appealing idea to the charter board, but members said it’s too early to judge One World’s chances of approval. The board must vet One World’s plans to ensure that the founders have the wherewithal to execute their vision.

Charter board Chairman John H. “Skip” McCoy said he will be looking for evidence that One World’s founders are equipped to teach all of the D.C. students who might walk in the door, including those who have grown up in poverty or are years behind in reading. Charter schools are open to children citywide and use lotteries when demand exceeds space.

“You’re not going to be able to pick who you get, and obviously, the backgrounds will be quite different than what you get at Sidwell,” McCoy said.

Board members also said it’s far from clear what the proposed school’s association with Sidwell means.

One World’s application refers to a “partnership” with Sidwell that would include advice in writing curriculum and training teachers, among other things. Founders referred again to that partnership at Monday’s public hearing on their proposal.

Sidwell officials said they have not agreed to any formal arrangement but are interested in considering ways to be involved with the charter school if it is approved. “At this point, it’s unclear what direction that might take,” said Ellis Turner, Sidwell’s associate head of school.

One World’s founders also wrote in their application that they had received letters of support and endorsement from five well-known D.C. figures, including Donald E. Graham, the Washington Post Co.’s chairman and chief executive. But Graham has not written a letter, and he declined to comment on whether he intends to write one.

Three of the four others said to have written letters also have not done so, One World founders said in response to questions from The Washington Post. They said the inclusion of the names in the application was an error.

The founders include Lynch, who has worked as an administrator at other D.C. charter schools and, more recently, at a school in her father’s native Trinidad and Tobago.

Other founders are Sidwell alumna Kimberly Yates, who taught in community colleges, universities and abroad before becoming a reading specialist at KIPP College Prep, a D.C. charter school dedicated to preparing low-income students for college. Rickey Payton, a former Sidwell choral music teacher who now runs a performing arts academy in Silver Spring, would direct One World’s arts offerings.

Richard Lodish, who recently retired after more than three decades as principal of Sidwell’s lower school, also would be part of the new charter. Lodish — who began his career teaching in Cleveland in the late 1960s and helped start a charter school in Oakland, Calif., while on sabbatical a decade ago — has agreed to serve without pay for two years as One World’s part-time executive director.

Besides One World, eight other applicants have submitted proposals for new charter schools to open in fall 2014, including two Montessori schools and three alternative high schools for at-risk youths. The charter board, which is scheduled to vote on those proposals May 20, usually approves just a few of the applications it considers.