As if Mondays weren't tough enough as it is.

Standard & Poor's gave the world markets a reason to hate this Monday more than most as it put a "negative" outlook on the U.S.' credit rating. In short, what that means is that the S&P has put the U.S. on its naughty list and may lower the country's credit rating from AAA.

Let's go ahead and call a spade a spade here, though -- the stock market sell-off in the wake of the announcement is pretty silly.

Granted, there would be a definite impact for many companies if the U.S. were, in fact, downgraded. Insurance companies such as Hartford Financial (NYSE: HIG), Metlife (NYSE: MET), and Progressive (NYSE: PGR) tend to hold sizable chunks of Treasuries and could be hurt if prices started falling. Meanwhile, companies with significant debt loads such as GE (NYSE: GE), Caterpillar (NYSE: CAT), and DuPont (NYSE: DD) could see borrowing costs rise if Treasury yields started to rise.

But ...

Take a deep breath
First of all, the S&P report suggested that there's a 1-in-3 chance that the rating agency will lower the U.S.' rating over the next two years. Hogwash. S&P has final say over whether that actually happens, but that's nonsense. There's certainly a very non-zero chance of the U.S. needing a downgrade, but is there really a one-third chance that the U.S. will need to be downgraded to be in line with Slovenia, Spain, and Chile?

And as far as accuracy in judging creditworthiness goes, perhaps it's a cheap shot to bring up those pesky mortgage and other structured securities that S&P and fellow raters Moody's (NYSE: MCO) and Fitch deemed to be of AAA mettle before they cost investors billions (trillions?), but it's not like that experience is ancient history.

Of course, it seemed that equity investors were the only ones significantly sweating S&P's move. The dollar fell against the yen but rose against the euro, while the yield on 30-year Treasuries fell.

Perhaps bond investors are looking at this from a broader historical context. As economist and New York Times columnist Paul Krugman pointed out, after S&P cut Japan's rating in 2002, yields on the country's debt stayed ridiculously low. So low, in fact, that -- as Krugman also notes -- betting against Japanese bonds came to be known as the "trade of death."

The real story
An economist from Nomura Securities had an interesting quip on the outlook change, saying "S&P has served a useful public service by putting all parties on notice that words and actions in the political debate have consequences."

Amen to that.

In other words, this ruler-on-the-knuckles from S&P may be meant primarily as a wake-up call to U.S. politicians to urge them to act more like grown-up leaders of a country and less like snotty schoolchildren. The brinkmanship during the U.S. budget debate -- which nearly brought the government to a standstill -- may have just been a warm-up for the showdown on the debt ceiling. And if Congress can't get its act together on these shorter-term matters, is there really hope for them to tackle more significant challenges like the longer-term fiscal road map?

S&P's "1-in-3" probability on downgrading the U.S. is bogus. However, I certainly hope the rating agency's message is able to get through the thick skulls of the folks in Washington so we can start seeing some real progress on mapping the country's financial future.

Health care is one of the biggest challenges the U.S. faces. My fellow Fool Morgan Housel recently asked: How would you fix the health-care system?

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