With her latest full-length concert special, “Assassin,” Margaret Cho continues to mine the riches of her niche audience with material geared to appeal to them but falling short of universal appeal.

Cho riffs on news and political stories of summer 2004 when this tour was recorded, far from the sort of observational humor comedians assemble for talk show appearances and the like. She combines this with cultural material commenting on both Asians and gays or of interest to one group or another.

Her material becomes so dependent on her persona and the points she wants to make that it slides into advocacy and away from comedy at points. Performing before her target audience, the applause seems to come more for the political points she is making than for the humor.

Occasionally, Cho does strike a comedic chord with the attitude and intelligence of the material, observing that Martha Stewart was basically sent to jail for “being a bitch,” and if that applied to her, Cho would get “consecutive life sentences.” Later, she also recalls a joke that got her right-wing hate mail – saying that George Bush really wasn’t Hitler like some critics say, but would be if he actually applied himself a little more. This becomes the catalyst for a highlight of the performance, being her reaction and her fans’ reaction to the hate mail.

The end result is that Cho’s act seems mildly amusing, with a few moments of brilliance here and there, but not quite as compelling as one might like.