After using her coincidentally convenient knowledge of hair care products to acquit a murder suspect in "Legally Blonde," one-dimensionally ditzy Harvard Law grad Elle Woods (Reese Witherspoon) has become a naively sanguine congressional aide for the insipid sequel "Legally Blonde 2: Red, White and Blonde" -- and once again her dumb luck masquerades as unsuspected smarts.

With Elle in Washington to lobby against animal testing by cosmetics companies, the plot turns on her ability to win over two bitterly conservative senators -- not with reason, facts or even charm, but simply because one of them happens to be a sorority sister (they have a secret dance instead of a secret handshake) and another has a big male Rottweiler who just happens to fall in love with Bruiser, her little male Chihuahua, during a walk in the park.

Yes, that's right -- this feebly scripted, Barbie-brained, Gucci-accessorized so-called comedy actually climbs up on a designer-pink soapbox of social consciousness to preach in platitudes about both animal rights and gay rights. Advocates in both camps should feel insulted.

Despite being all skin-deep causes and musical montages ("I taught Bruiser how to shop online, I think I can handle Congress!" chirps Elle as lead-in to a girly-pop-scored tour of D.C. landmarks), "Blonde 2" genuinely expects empathy for the ersatz earnestness of its half-witted heroine (instead of for the politicians and their snooty staffers who, quite justifiably, find the girl's perky cluelessness insufferable).

Within her last three studio movies (including the first "Blonde" and "Sweet Home Alabama"), Witherspoon's once-intrepid talent ("Freeway," "Election") has withered into a sprightly sleepwalk of romantic comedy clichés (here she's also planning a cutesy-poo wedding) and bumper-sticker-deep believe-in-yourself messages. What's left of her charisma is all that holds together this stupefying script, in which Elle's spunkiness is the only weapon she needs to defeat corporate contributions and willful legislative morass.

Bob Newhart adds an undervalued touch of his understated humor as Elle's doorman, whose years in Washington have given him some political savvy. Deprived of even a single funny line, Sally Field keeps on an even keel as Elle's employer, a senator who is losing her soul over compromising her principles. Jennifer Coolidge reprises her role as Elle's aging-bimbo cosmetologist pal, who comes to the capital for a pick-me-up makeover when Elle feels defeated.

But director Charles Herman-Wurmfeld ("Kissing Jessica Stein") provides only two moments of real comedic sparkle -- both one-liners from one-scene actors. The first comes from a nerdy scientist at a cosmetics lab, explaining why he can't free Bruiser's mom (who is the only reason Elle took up the animal rights cause in the first place) because his access privileges have been revoked. "You swallow one key," he laments, "and suddenly you're the weird key-swallowing guy."

The other comes from the wonderfully droll, hilariously rubber-faced Jackie Hoffman (also from "Kissing Jessica Stein") as a doggie salon receptionist who breaks it to Elle and a gruff, traditionalist Southern senator that "Your dogs are gaaaayyyy." (Soon they're decked out in little leather outfits.)

After each of these scenes, "Blonde 2" slides right back into its innate, intelligence-insulting ludicrousness, which culminates in Elle giving a rousing animal rights speech (using hair care again as a metaphor) to a joint session of congress as the music swells and all the elected officials start nodding with tears forming in their eyes.

Afterwards (and just before a short-handed where-are-they-now finale that skips right over plot resolution and just ties up loose ends) someone actually says to her, "None of us ever thought one person could do this much until you came along."

Yeish. The idea that somebody got paid -- a lot -- to write this crap is quite simply beyond belief.