The Supreme Court, for all its shameful decisions about Citizens United, left an opening for Congress to right the wrong: pass a law requiring disclosure of the identities of donors to candidates via those embarrassing "social welfare" organizations called Super PAC's.
The justices wanted voters to be able to decide for themselves “whether elected officials are ‘in the pocket’ of so-called moneyed interests.”
The court advised such disclosure in its otherwise disastrous Citizens United decision in 2010, which loosed a new wave of unlimited spending on political campaigns. The decision’s anticorruption prescription has grown even more compelling as hundreds of millions of dollars in disguise have flooded the 2012 campaigns... NYT editorial board
Not a single Senate Republican voted to pass the bill, "filibustering it to death" as the Times suggests. Only one shaft of light comes from that debacle: voters now know exactly who killed the bill. In the long term, the Democrats may benefit significantly from the Senate Republicans' failure.