A majority of Obama voters who switched to Brown said that "Democratic policies were doing more to help Wall Street than Main Street."
A full 95 percent said the economy was important or very important when it came to deciding their vote.
In a somewhat paradoxical finding, a plurality of voters who switched to the Republican -- 37 percent -- said that Democrats were not being "hard enough" in challenging Republican policies.
It would be hard to find a clearer indication, it seems, that Tuesday's vote was cast in protest.
The poll also upends the conventional understanding of health care's role in the election. A plurality of people who switched -- 48 -- and didn't vote -- 43 -- said that they opposed the Senate health care bill. But the poll dug deeper and asked people why they opposed it. Among Brown voters, 23 percent thought it went "too far" -- but 36 percent thought it didn't go far enough; 41 percent said they weren't sure why they opposed it.
For voters who stayed home and opposed health care, a full 53 percent said they opposed the Senate health care bill because it didn't go far enough; 39 percent weren't sure and only eight percent thought it didn't go far enough.
The firm Research 2000 conducted the post-election survey Tuesday night on behalf of three progressive organizations -- the Progressive Change Campaign Committee, Democracy for America and MoveOn.org.
The firm discovered that 18 percent of Obama backers who voted in the Senate race ended up casting ballots for Brown.