“1776” is a big show with big themes. The musical — which had blockbuster Broadway runs in 1969 and 1997 and is on now through May 19 at Ford’s Theatre — chronicles the writing and signing of the Declaration of Independence and the difficult compromises that had to be made to get it done.

The play is set in Philadelphia’s Independence Hall, where the Continental Congress signed the declaration. Staging a production at the theater where Lincoln was shot adds another layer to the experience, for the actors as well as the audience.

“All the discussion [that led to the Declaration] in some ways came to an end in that building,” says Stephen Schmidt, who plays Richard Henry Lee, the Virginia statesman who made the formal motion calling for the colonies’ independence from England. “Not to mention the image of Gen. George Washington is there the entire time. It was unexpected how resonant it is in that room. It almost feels like a sacred mission.”

With its large cast, period costumes and bombastic musical numbers, the show certainly has its share of grandiosity. But it also finds inspiration in small moments — and in quite a few small parts. Though several of the show’s actors appear only briefly, they’re a big part of a moving story. And they use their off-time wisely.

Erin Kruse (Martha Jefferson)

Erin Kruse, who plays Thomas Jefferson’s wife, Martha, enters the stage with a bang. “My first interaction is literally me running on to see my husband for the first time in six months. I run into his arms and kiss him for about 90 seconds,” she says.

Erin Kruse plays Martha Jefferson, who has just two scenes in “1776.”

Kruse also appears in the next scene, when she sings a song to John Adams and Benjamin Franklin about the allure of her violin-playing husband. Her song is a change from most of the show, which takes place in the stuffy room where the Congress is meeting. “I think Martha is put in the show to give some fresh air and femininity to it,” says Kruse.

Kruse gets called in much later than the rest of the cast, but she still has to hang around for the show’s 2½-hour duration. She spends that time preparing for another patriotic show. “I’m from a small town in Kansas, and we have a really big Fourth of July celebration,” she says. “I just started working on a cabaret-style show to put on this summer. It’s actually a thank-you and a tribute to my hometown.”

Kate Fisher (Abigail Adams)

Abigail Adams was one of her husband John Adams’ biggest supporters, keeping the home fires burning while he was off helping to found the country. In “1776,” she fills a similar role. “When she comes on, it’s when everything has gone to pot,” says Kate Fisher, who plays Abigail. “Those three instances in the show is when she changes the current for him.”

Yes, Abigail appears onstage only three times, for less than 30 minutes total. But Fisher says she relishes doing a show that gives her a chance to catch her breath: She usually plays “girls who won’t shut up and never stop moving.” The downtime comes at a price, though. “When you’re onstage with a massive role, it’s easy to go, go, go. When you’re gone a lot of the time, the energy changes. You have to keep yourself focused.”

Fisher uses her downtime to warm her voice before every entrance and also to do some light crafting. “I have three friends who have just given birth, so I’m making baby blankets,” she says.

Stephen Schmidt (Richard Henry Lee)

Richard Henry Lee doesn’t have the gravitas one might associate with one of our nation’s founders.

“The script describes Lee as ‘a buffoon,’” says actor Stephen Schmidt. “But he is a good-natured, well-meaning buffoon.”

Lee is asked to introduce the bill advocating for America’s independence from Britain because he’s popular — as opposed to Adams, who is repeatedly described as “obnoxious and disliked.” Franklin first suggests Lee for the task, “and of course Adams is like, ‘Are you kidding me? This guy is an idiot,’” says Schmidt. Lee’s song is his defense to that charge. And it goes on for a while. “It makes Adams crazy because he can’t get him off the bloody stage. He keeps coming back for another encore.”

Lee then leaves for Virginia and returns with the proposal, only to leave again to become governor of the state — never to return to the sweltering room in Philadelphia, though the show goes on for another two hours.

“I have a lot of reading I like to do,” says Schmidt of his off-time. “I keep thinking I’m going to get tired of reading history, but it hasn’t happened yet.”

Ford’s Theatre, 511 10th St. NW; through May 19, $15-$80; 202-347-4833. (Metro Center)