Here's a very quick sketch gleaned from the info available:
It could be $500 billion to $1 trillion, says Ala. Sen. Richard Shelby, among the most skeptical of the Congressional Republicans briefed last night by Fed chief Ben Bernanke and Treasury Secretary Hank Paulson.
That's roughly the price range of the Iraq War, which has cost taxpayers about $500 billion so far - plus $600 million in interest payments -- and another $280 million to replenish military equipment, according to estimates by economists earlier this year.
So much for President Bush's dream of eradicating the nearly $500 billion budget deficit by 2012.
But there's a possible platinum lining. The mortgage-backed securities likely to be bought by Treasury (which is likely to be the initial purchaser, according to reports) are not without value. They are just impossible to value by a panicky, pessimistic market. When (or if) the market stabilizes, prices might actually rise and the government could actually profit from the most innately valuable of the securities that are bought.
Of course, that could take years -- and the massive borrowing required to backstop the markets could spike inflation in the near or medium term, economists say.