The U.S. government is close to maxing out its credit limit. Again.

This week the U.S. Treasury Department will hold a slew of bill and bond sales, pushing the amount of debt the government owes precariously close to the federal debt ceiling of $12.1 trillion. The debt ceiling is a self-imposed limit on the amount of money the country is permitted to borrow. As of today, the national debt stood at a $11.9 trillion . Trillion. With a "T." That's $110,135 for every U.S. taxpayer. And you thought your credit-card bills were bad.

It won't be the first time the government has maxed out its credit limit. Congress has boosted the ceiling 76 times since 1960, twice in the last two years alone. Lawmakers last raised the ceiling in February of this year.

Unless lawmakers quickly vote to raise that ceiling, the government may be forced to use some sleight of hand to shift or sell off some debt held in government accounts, such as bonds held in pension and retirement funds for federal workers. (Of course those investments would have to be repaid, with interest.) If that's doesn't work the government may be forced to shut down, as it did twice in 1995.

Is the threat of a government shutdown enough to push lawmakers to raise the ceiling for the second time this year? In the past, government shutdowns have led to little more than mild inconvenience for citizens. Still, shutting down the government because it's maxed out its credit line would be humiliating for lawmakers -- and provide a field day for the media -- so it's likely Congress will try to avoid it.

Indeed, most economists expect lawmakers to vote to raise the ceiling before the public debt maxes out, and to lift it substantially enough so that lawmakers aren't forced into voting for another embarrassing increase anytime soon. A vote to raise the ceiling also gives politicians the perfect opportunity to highlight the administration's runaway spending and call for more restraint in the federal budget.

Still, our Treasury bonds, bills and notes are still viewed as solid investments by credit-rating agencies. Standard & Poor's gives the U.S. a AAA rating, its highest investment grade. (Essentially, that means the U.S. government can be counted on to repay all its debts, with interest.)

For American taxpayers, soaring U.S. debt could have far more painful consequences. Unless it finds some way to make huge cutbacks in its expenditures, Congress may soon need to raise money -- in the form of higher taxes -- to keep up with its debt payments.

Terri Cullen is an award-winning financial journalist. She was one of the original team of editors who helped to launch The Wall Street Journal Online. Terri is also the author of "The Wall Street Journal. Complete Identity Theft Guidebook." Read her bio to learn more about her.

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