There are directly appropriated US government spending on the TARP. Then there's Fed lending, which is different. Then there are various loan guarantees and agreements to backstop questionable assets. These are all very different kinds of expenditures and some of them don't even really count as 'spending' in the ordinary sense we understand the term.

Exhibit A: This chart, which has been making the rounds in the blogosphere:

Bloomberg News kicked off the frenzy with this story -- which has mysteriously disappeared after getting top billing on the Drudge Report and dozens of other Web sites and blogs -- tallying the cost of the bailout at well over $7 trillion. Then, finance blogger Barry Ritholtz posted this teaser for his upcoming book, Bailout Nation:

If we add in the Citi bailout, the total cost now exceeds $4.6165 trillion dollars.

People have a hard time conceptualizing very large numbers, so let’s give this some context.

The current Credit Crisis bailout is now the largest outlay In American history.

Crunching the inflation adjusted numbers, we find the bailout has cost more than all of these big budget government expenditures – combined:

• Marshall Plan: Cost: $12.7 billion, Inflation Adjusted Cost: $115.3 billion
• Louisiana Purchase: Cost: $15 million, Inflation Adjusted Cost: $217 billion
• Race to the Moon: Cost: $36.4 billion, Inflation Adjusted Cost: $237 billion
• S&L Crisis: Cost: $153 billion, Inflation Adjusted Cost: $256 billion
• Korean War: Cost: $54 billion, Inflation Adjusted Cost: $454 billion
• The New Deal: Cost: $32 billion (Est), Inflation Adjusted Cost: $500 billion (Est)
• Invasion of Iraq: Cost: $551b, Inflation Adjusted Cost: $597 billion
• Vietnam War: Cost: $111 billion, Inflation Adjusted Cost: $698 billion
• NASA: Cost: $416.7 billion, Inflation Adjusted Cost: $851.2 billion

TOTAL: $3.92 trillion

Now, I am pretty sure that Ritholtz, a finance whiz, understands full well that the $4.6 or $7.7 trillion isn't all "outlays." As Zachary Roth explains, only "some of these commitments -- for instance, the Treasury's bailout program -- represent actual spending":

We could see a return on these investments, of course, depending on how the companies that we've taken on fare going forward, but there are by no means any guarantees.

Others, meanwhile, represent loans backed by collateral, meaning the government would have had to have badly miscalculated for us not to be paid back in full, probably with interest. And some are simply loan guarantees.

So putting an exact figure on exactly how much we've put up doesn't tell us much.

But not everyone knows this. Witness Cory Doctorow's misleading headline on Boing Boing: "Bailout costs more than Marshall Plan, Louisiana Purchase, moonshot, S&L bailout, Korean War, New Deal, Iraq war, Vietnam war, and NASA's lifetime budget -- *combined*!" Is it any wonder people are so upset?