The appearance of impropriety

Look, I don't know if Jay Rockefeller received campaign donations from the telecoms intended to help them with their immunity quest (he should probably recuse himself in some fashion, though,) but take a look at the AT&T defense of the allegations.

A spokeswoman for AT&T, Claudia B. Jones, said contributions from its executives related to Mr. Rockefeller’s role on the Senate Commerce Committee, not immunity or other questions before the Intelligence Committee.

We weren't trying to bribe him over immunity. We were trying to bribe him over regulation. Oh, that's so much better.

She added that although industry executives and politicians might not always agree, it is “commonplace for AT&T employees to regularly and voluntarily participate in the political process with their own funds.”

Because "political process" means donating to Senators you want something from.

(How does a Rockefeller allow himself to get in trouble over 42K?)