At Ars Technica, Tim Lee counts the Senators who have announced their opposition to the Protect IP Act, and writes:

The newly-opposed Senators are skewed strongly to the Republican side of the aisle. An Ars Technica survey of Senators’ positions on PIPA turned up only two Democrats, Ben Cardin (D-MD) and Jeff Merkley (D-OR), who announced their opposition on Wednesday. The other 11 Senators who announced their opposition on Wednesday were all Republicans. [Late updates tally four more newly-announced Republican opponents, including one more who had previously been a sponsor.]…

The partisan slant of the defections is surprising because copyright has not traditionally been considered a partisan issue. Before Wednesday’s protests, PIPA had 16 Republican co-sponsors and 23 Democratic ones. The bill lost a quarter of its Republican sponsors on Wednesday, while we know of only one Democrat, Ben Cardin (D-MD), who dropped his support.

While Tim goes on to note the opposition from Heritage and RedState discussed here this morning, the other side of this is that the biggest supporter of SOPA/PIPA is the Motion Picture Association of America, headed by former Democratic Senator Chris Dodd. You might think that a Senate career that ended with a series of scandals would blunt Dodd’s influence, but you’d be wrong; Hollywood maintains a strong grip on the Democratic Party.