Bloomberg tells the story in detail, but here is the money quote:

Now that the collapse has occurred, the roadblock built by Senate Democrats in 2005 is unforgivable. Many who opposed the bill doubtlessly did so for honorable reasons. Fannie and Freddie provided mounds of materials defending their practices. Perhaps some found their propaganda convincing.

But we now know that many of the senators who protected Fannie and Freddie, including Barack Obama, Hillary Clinton and Christopher Dodd, have received mind-boggling levels of financial support from them over the years.

Throughout his political career, Obama has gotten more than $125,000 in campaign contributions from employees and political action committees of Fannie Mae and Freddie Mac, second only to Dodd, the Senate Banking Committee chairman, who received more than $165,000.

For the first time in nearly six months John McCain has pulled out in front of Barack Obama in the RealClearPolitics average tracking poll. 

Because the RCP average uses a rolling average of the polls from several organizations, it is good for spotting trends and rounding out anomalous results.