Bill

The first example that comes to mind is a study of the impact of the  
Congressional bank "scandal."  Gary Jacobson, among others, showed a  
substantial impact of that event on the chance of reelection success.

The best known analyses of congressional approval are probably:

Durr, Gilmour, and Wolbrecht.  Explaining Congressional Approval (1993  
AJPS)

Hibbing and Theiss-Morse. Congress and Public Enemy (1995 book, see  
also "What is it about Government that Americans Dislike?")

In both cases, the scholars find that major scandals do have a  
negative impact on congressional approval.  That is not surprising.   
What may be more surprising is that Congressional approval suffers  
when Congress does its job (at least by the understanding of political  
scientists): proposes, debates, and passes legislation.  Americans  
react negatively to political disagreement and conflict, which some  
might say is endemic to legislative decision making.   Ironically from  
the perspective of democratic theory, the most closed and opaque an  
institutions' decision making process (think Supreme Court), the most  
positive the public evaluations.

And yes, the implication is that the last decade of partisan  
infighting and lack of comity in Congress have only made things worse.

As to Citizens United, I have seen no such analyses, and it's unlikely  
that you could find any relationship between Citizens United and  
congressional approval.  I am very skeptical that the public will make  
any link between the two.
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Paul Gronke                Ph:  503-517-7393
			               Fax: 734-661-0801

Professor, Reed College
Director, Early Voting Information Center 3203 SE Woodstock Blvd.
Portland OR 97202

EVIC: http://earlyvoting.net