Keith Olbermann’s history of baseless conspiracy-mongering is well-documented, and he was at it again tonight. First, he showed the tapes from the day before Katrina hit, which the press and the Democrats have been using to attack Bush. He didn’t question where they came from or why they became such big news this week. Then he showed the tapes from the day of the storm, which show Michael Brown praising Bush’s response. But first, he noted that the latter had been leaked by “Republican officials” and called their release “conveniently timed.”

Funny how Olbermann didn’t see anything “convenient” about a Katrina-tape “scandal” that broke just as the furor over the last “scandal” — the Dubai ports deal — was starting to die down.

Olbermann also seems to think Bush’s trip to India is another “convenient” way for him to change the subject from Katrina — as if this major international visit was just slapped together on Tuesday.

Next, Olbermann and Dana Milbank had a dishonest conversation about why Bush is such a big liar. The previous segment had shown a clip of Bush saying, “I don’t think anybody anticipated the breach of the levees,” followed by a clip of National Hurricane Center Director Max Mayfield from the first video saying, “I don’t think anyone can tell you with any confidence right now whether the levees will be topped or not, but that’s obviously a very very grave concern.” The segment then showed a clip of Mayfield explaining his comments (excerpted below from MSNBC.com):

“Nobody talked about the possibility of a levee breech or failure until after it happened,