White House Philosophy Stoked Mortgage By JO BECKER, SHERYL GAY STOLBERG and STEPHEN LABATON

It was Sept. 18. Lehman Brothers had just gone belly-up, overwhelmed by toxic mortgages. Bank of America had swallowed Merrill Lynch in a hastily arranged sale. Two days earlier, Mr. Bush had agreed to pump $85 billion into the failing insurance giant American International Group.

The president listened as Ben S. Bernanke, chairman of the Federal Reserve, laid out the latest terrifying news: The credit markets, gripped by panic, had frozen overnight, and banks were refusing to lend money.

Then his Treasury secretary, Henry M. Paulson Jr., told him that to stave off disaster, he would have to sign off on the biggest government bailout in history.

Mr. Bush, according to several people in the room, paused for a single, stunned moment to take it all in.

“How,” he wondered aloud, “did we get here?”....