…in 2005 Alan Greenspan told Congress how urgent it was for it to act in the clearest possible terms: If Fannie and Freddie “continue to grow, continue to have the low capital that they have, continue to engage in the dynamic hedging of their portfolios, which they need to do for interest rate risk aversion, they potentially create ever-growing potential systemic risk down the road,’’ he said. “We are placing the total financial system of the future at a substantial risk.’’

What happened next was extraordinary. For the first time in history, a serious Fannie and Freddie reform bill was passed by the Senate Banking Committee. The bill gave a regulator power to crack down, and would have required the companies to eliminate their investments in risky assets. . . .

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.

Clinton, the 12th-ranked recipient of Fannie and Freddie PAC and employee contributions, has received more than $75,000 from the two enterprises and their employees. The private profit found its way back to the senators who killed the fix.

There has been a lot of talk about who is to blame for this crisis. A look back at the story of 2005 makes the answer pretty clear.

One of the giant mortgage companies at the heart of the credit crisis paid $15,000 a month from the end of 2005 through last month to a firm owned by Senator John McCain’s campaign manager, according to two people with direct knowledge of the arrangement.

…

From 2000 to the end of 2005, Mr. Davis received nearly $2 million as president of the coalition, the Homeownership Alliance, which the companies created to help them oppose new regulations and protect their status as federally chartered companies with implicit government backing. That status let them borrow cheaply, helping to fuel rapid growth but also their increased purchases of the risky mortgage securities that proved to be their downfall.