If it weren't for Ice Cube's charismatic bad attitude, "XXX: State of the Union" would be downright unwatchable.

A paper-doll sequel with paper-thin performances and a video-game plot -- a ridiculously implausible presidential coup planned by an arch-conservative Secretary of Defense (teeth-gritting Willem Dafoe) -- this is nothing but a sorry attempt to ride the explosion-shredded coattails of 2002's "XXX" without bringing back its star. Vin Diesel apparently got a big head from having the first picture custom-tailored for him, and was booted after asking for $25 million to reprise his role as an extreme-sports-jock spy.

So instead, Cube plays a Navy SEAL imprisoned for insubordination who is busted out by loose-cannon National Security Agency honcho Samuel L. Jackson (tough-guying his way to an easy paycheck) and deputized as the new Agent Triple-X after Jackson's underground headquarters is raided by gadget-laden baddies in black body armor. Who these thugs are and what they were doing there is barely explained, and no reason is offered for why, with all its agents, intelligence and firepower, the NSA must rely on a lone prison escapee to investigate and thwart a takeover of the U.S. government.

But director Lee Tamahori (who helped dumb down the last James Bond movie) doesn't really care as long as the next 5,000-round shoot-out, five-story fireball or $500,000 sports-car chase is just around the corner. This is the kind of brain-dead action movie in which window-rattling, wind-generating helicopters inexplicably sneak up on people, characters "lie low" by squealing around street corners in Washington D.C. while driving tricked-out, iridescent pimp-mobiles, and federal agents have to be certifiable morons in order for the plot to advance.

The actors seem largely embarrassed and apathetic (especially the already lackluster Scott Speedman, playing one of those obtuse feds) and the actresses (I use the word loosely) are cast for their cheap silicone cleavage, and not for their ability to, say, deliver a credible line of dialogue or even convincingly walk across a room and smile.

What's worse, in the non-stop pageant of overblown action set pieces, each is so routine that they quickly become boring. "XXX2" has one exciting scene -- Ice Cube's prison break -- which nonetheless requires enough suspension of disbelief for a whole movie all by itself. The lack of security is laughable, although it's nothing compared to the ease with which Cube and a HumVee convoy of homeboys breach the defenses around the Capitol during the State of the Union address in the picture's climax.

Through the sheer photogenic ferocity of his trademark scowl, Ice Cube manages to cruise through this hailstorm of garbage without getting any on him. But now he's off the hook because this sequel establishes that there will be a different Triple-X in each "XXX" movie, so if "State of the Union" turns a profit, just imagine how bad the next one could be.