The power to bail out businesses comes from where all legitimate power comes: the consent of the people who are governed. In this case, people WANT to be "bailed out."
More than half of the people who live in this country take more than they give in taxes when it comes to Feddollars. Since this is an election year, and the electorate is screaming for them to do SOMETHING, they did what they do best: resorted to the printing press and handed out over $1 trillion. First, they mailed most of the people a check, then they gave cash to business and special interests.
It is my opinion that we will see more of this as the economy worsens, as it must, because we are borrowing and printing more and more money as time goes on.