The temple opened in 1974, shortly after another high-profile Mormon -- George Romney, Mitt's father -- left his post as Richard Nixon's secretary of Housing and Urban Development.
"The Washington temple served as a symbol of the triumphant return of Mormonism to the east," says Givens, the University of Richmond professor. "Mormons left from the point of a bayonet in the 1800s and the temple is this gigantic symbol that says 'We're back -- and we're back in the nation's capital.' "
Unlike Mormon meetinghouses, where members meet for Sunday worship, temples are grander buildings reserved for certain rites, such as proxy baptisms for the dead.
To this day, the first monument many Washington visitors see isn't a federal landmark. It's the massive Mormon temple, its Georgian marble towers and gold-leafed spires looming above the trees on the Washington Beltway like an otherworldly castle.
The temple houses a J. Willard Marriott-financed mural of Jesus Christ's second coming, which features a picture of the Washington temple itself in the background.
"Are you implying that the millennium will begin in Washington?" a temple visitor once asked Marriott, referring to Jesus' return.
Replied Marriott: "What better place is there?"
Good at organizing
These days, the Mormon impulse toward Washington is often as much political as patriotic.
Patrice Pederson - the campaign manager for the Mormon running for president in Mali - made her first foray into politics at 15, hopping the bus from her home in the suburbs of Salt Lake City into town to intern with a Republican candidate for the U.S. House.
"I remember that when Bill Clinton was elected, I wore all black to school that day," says Pederson, who was in junior high at the time. "I was mourning the death of liberty."
When then-Vice President Al Gore visited Utah, Pederson protested his speech with a homemade poster that said "Blood, Guts & Gore -- Healthcare'94." (She can't recall the poster's exact meaning).
Pederson's activism as a "total hardcore right-winger" continued into her 20s. She put off college at BYU to start a "pro-family" advocacy group aimed at lobbying foreign governments and the United Nations. The work brought her to Washington so frequently that she decided to relocate last year: "I had more friends here than in Utah."
Pederson's path to D.C. speaks to the growing Mormon/Republican alliance since the 1960s, driven largely by the emergence of social issues such as abortion and gay marriage and the rise of the Christian Right.
"In the 1950s and '60s, Utah became Republican," says Bushman. "It's partly about being anti-communist, but it's also a response to the 1960s and the decay of old-fashioned moral virtues. It's an anti-1960s movement, and the Republicans seemed to be the party of old-fashioned virtues."
Pederson's roommate, Kodie Ruzicka, grew up squarely in that movement, with her mom heading the Utah chapter of Eagle Forum, a conservative Christian group founded by rightwing icon Phyllis Schlafly.
In the 1970s, when the Catholic Schlafly led a successful grassroots campaign against the Equal Rights Amendment, which would have made gender-based discrimination unconstitutional, she enlisted the help of Mormons.
To its opponents, including the LDS Church, the ERA was the work of radical feminists who wanted to upend traditional gender roles.
Much of Schlafly's organizing was among evangelicals, and "given the sometimes hostile evangelical line on Mormons, [Schlafly's] Mormon outreach was kind of revolutionary," says Ruzicka, who now works at the Justice Department. "But we're good at organizing, and we have a lot of useful structures for it, so that was useful to her."
Today, Mormons head Eagle Forum chapters across the West, including California, Arizona and Nevada, as well as Utah.