Not very. A reader comments:
I just thought I would also observe that according to the Fox New story in your link:
"A breath test indicated Gibson's blood-alcohol level was 0.12 percent, Whitmore said. The legal limit in California is 0.08 percent."
0.12 is certainly over the line for impaired driving skills, but it is not so very high that Mel would be 'speaking in tongues,' with no connection between his statements and his own internal thought process. At that level of intoxication he simply would be a little freer of social inhibitions, and I suspect that his statements would reliably reflect his thought processes, perhaps even especially so.
The only thing with which I disagree with you is that his career will be over. One highly publicized week in a rehab clinic, a Larry King interview, and he’ll be back, bigger than before, with his Christianist fans more in love with their hero than ever. There really is no such thing as bad publicity in the 21st Century.
I wonder whether Christianism as a movement can tolerate a drunk, rabid anti-Semite as one of its cultural icons? We'll see.