My pick would be the Massachusetts Democrat Congressman Barney Frank.
Here he is in 2005 claiming that fears of a housing bubble are unfounded.
Here’s the timeline showing who wanted to regulate Fannie and Freddie, and who blocked regulation.
Here’s video from a hearing showing Democrats opposing regulations:
That’s right – Republicans wanted to regulate Fannie Mae and Freddie Mac, and Democrats said Fannie Mae and Freddie Mac are “doing a tremendous job”.
Fannie Mae and Freddie Mac had paid the Democrats off handsomely during multiple election cycles, but I’m sure that the Democrats’ opposition to regulations had nothing to do with those political contributions.
I found these videos at Ace of Spades, thanks to ECM.