Can Congress be Bought? - Resistance to Change #10

Yes.  In fact, the Return on Investment can't be beat:

Republican Strength In Congress Aids Super-Rich, President's Affiliation Has No Effect
"According to the study, "The Rise of the Super-Rich: Power Resources, Taxes, Financial Markets, and the Dynamics of the Top 1 Percent, 1949 to 2008," following years of relative stability post World War II, the income share of the top 1 percent grew rapidly after 1980—from 10 percent in 1981 to 23.5 percent in 2007, a 135 percent increase. The income share of the super-rich dropped to about 21 percent in 2008, likely as a result of the financial crisis that had begun, Volscho said. By way of comparison, the income share of the top 1 percent was 11.7 percent in 1949.

"We found evidence that congressional shifts to the Republican Party, diminishing union membership, lower top tax rates, and financial asset bubbles in stock and real estate markets played a strong role in the rise of the 1 percent," said Volscho

... From 1949 through 2008, the impact of a one percentage point increase in the share of seats (just over five seats) held by Republicans in Congress raised the top income share by about .08 percentage points, according to the study.

"At first glance, this might seem negligible, but that's really not the case," said Volscho. "Given that the estimated national income in 2008 was more than $7.8 trillion, an increase of only 1 percent in Republican seat share would raise the income of the top 1 percent by nearly $6.6 billion. That equates to about $6,600 per family in the top 1 percent."

In terms of labor unions, over the course of the study period, Volscho and Kelly found that a one percentage point decrease in union membership among private sector workers was associated with more than a .40 percentage point increase in the income share of the super-rich. According to Volscho, private sector union membership was 34.9 percent in 1949, but had dropped to 7.6 percent by 2008.

Based on the estimated 2008 national income, the effect of a one percentage point drop in private sector union membership would transfer $33.4 billion to the top 1 percent, Volscho said. ...

Study: The Rise of the Super-Rich: Power Resources, Taxes, Financial Markets, and the Dynamics of the Top 1 Percent, 1949 to 2008.
http://www.asanet.org/journals/ASR/Oct12ASRFeature.pdf