Silk mikado gathered shoulder cocktail dress, Carolina Herrera ($2,290). Saks Fifth Avenue, Tysons Galleria, McLean, 703-761-0700; . Half-moon black onyx cabochons earrings, Jorge Adeler ($7,590). 772 E. Walker Road, Great Falls, 703-759-4076. Large pavé bubblegum ring.Silk mikado gathered shoulder cocktail dress, Carolina Herrera ($2,290). Saks Fifth Avenue, Tysons Galleria, McLean, 703-761-0700; . Half-moon black onyx cabochons earrings, Jorge Adeler ($7,590). 772 E. Walker Road, Great Falls, 703-759-4076. Large pavé bubblegum ring (LEFT HAND; $570) and pavé starstruck ring (RIGHT HAND; $372), MCL by Matthew Campbell Laurenza. Neiman Marcus, Tysons Galleria, McLean, 703-761-1600. Revolution ring, Bulgari ($8,950). The Collection at Chevy Chase, 301-986-8610

Danes, now 32, who studied for two years at Yale, jokes that as a native New Yorker, "I've been in therapy forever—I'm an armchair therapist at the very least." More seriously, she says, "Acting and psychology are not unrelated. They're both examinations of the human spirit.... I'm really curious as to how people work, particularly people with certain conditions that make them different to the rest of us."

Carrie's bipolar condition, for example, is defined by what Danes describes as its erraticism. "You can get some traction, but you're always on undulating ground. Most people can afford to be more casual in general, but there's a potential bomb inside Carrie, and she has to be hyper-vigilant." To get a handle on the more extreme phases of Carrie's illness, Danes discovered a surprising source: YouTube videos posted by manic-depressives while in their manic states. "I think they feel a strong urge to communicate their experiences, and the Internet is a great way to do that."

Slightly more daunting was the professional aspect of Carrie's character—her work at and knowledge of federal government departments and agencies, in particular the CIA. "I'm not particularly political," Danes says, adding that she has visited Washington only a handful of times, and never longer than for a couple of days. So before Homeland began filming last spring, Danes visited CIA headquarters at Langley, where a senior female officer assembled a broad group of colleagues for a discussion. "It was pretty amazing—they answered all my questions really honestly and directly. It is just such a fascinating culture and career," she says. "These are people who've dedicated their lives to doing this work. It's very demanding and high risk and isolating, and, therefore, often quite lonely. And they can't really talk about it with anyone, so there is not a lot of support."

While she says neither the Langley trip nor the show itself has awakened any latent political interest, she does profess to have a new kind of appreciation for her citizenship. "I'm more aware of how many people fight so hard and risk so much," Danes says. "That's a big deal, and it's easy to forget or not think about at all."