Eva Longoria arrives at her press conference Thursday. (Jason Reed/Reuters)

Venue: The east front of the Capitol.

Cause: Child migrant laborers.

Credentials: Star of long-running “Desperate Housewives”; executive producer of a documentary (“The Harvest”) about adolescent farmhands, whose educations are disrupted by back-breaking work.

Backup: Rep. Lucille Roybal-Allard (D-Calif.); advocates for labor and Mexican-American causes.

What she wants: Toughened child-labor laws that would lift the farmworker minimum age from12 to 14, and 18 for hazardous work, comparable to other industries.

How she looked: Hill-appropriate — it’s Hot Intern season, after all. Color-blocked purple-and-red fitted sheath dress that was half-prim, half-sizzling (exposed zipper, high hem). Towering purple platform heels.

Why this cause: While Longoria grew up on a Texas ranch, she made no claim of relating to migrants’ hardscrabble lives. “We were sheltered,” she said. “I have compassion for these people because I consume these products. . . These kids are not working on family farms, they’re working for big corporations.”

Side trip: Later stopped by Williams-Sonoma at Mazza Gallerie to sign copies of her new cookbook.