The next time you hear somebody freaking out about U.S. government debt, you can remind them that there has never been a better time for the government to borrow money -- ever.

The interest rate on 10-year Treasury notes fell on Wednesday to 1.63 percent, breaking a record low set in 1946, according to the Wall Street Journal.

There were some war bonds in World War II that had lower yields, but those did not trade actively, and the contemporary bond market really didn't exist then, noted Guy LeBas, chief fixed-income strategist at financial services firm Janney Montgomery Scott.

"In practical terms, this is the lowest it's ever been," LeBas said.

That's music to the ears of the U.S. government, which issued $1.6 trillion in marketable debt last year and another $562 billion in the first quarter of this year, according to market tracker Sifma.

But but but, some will sputter, America is eyeballs-deep in debt that it can never repay. Shouldn't interest rates be moving in the other direction? You know, higher? After all, people who don't pay their debts see their own interest rates skyrocket.

Here's the thing, though: Just about every other credit in the world is in even worse shape than the credit in the U.S. Among major developed sovereign borrowers, only Germany pays less to borrow than the U.S. -- about 1.27 percent for 10 years, at last check.

The U.S. and Germany are having an easy time borrowing right now mainly because they are seen as safe havens in a world where every other investment suddenly looks horrible. Europe is melting down, with Spain's 10-year borrowing costs pushing the dangerous 7 percent level. The euro earlier tumbled below $1.24, a two-year low against the U.S. dollar. China's massive economy is slowing down. U.S. stocks were tumbling again on Tuesday, pushing the Dow Jones Industrial Average to its lowest level of the year. As CNBC pointed out Wednesday, more than half of the companies in the S&P 500-stock index now have dividend yields higher than U.S. government bond yields. That's just extraordinary. Even gold has been a shaky safe haven lately.

Many will insist that investors are wandering into a trap by buying government debt at such low yields. The risk they're taking is that interest rates will snap higher at some point, which by the strange mathematics of the bond market will leave today's bond buyers with big losses. Such low interest rates are not justified, these critics argue, given that the economy is likely in better shape today than it was in, say, September 2008, when 10-year Treasury debt yielded more than 2 percent. A stronger economy should theoretically raise the risk of inflation, which the Fed will fight by raising interest rates -- again, punishing today's bond buyers.

"Treasuries have entered dangerous territory," wrote Agustino Fontevecchia of Forbes, in warning of an imminent bond market collapse. "The overcrowded trade will face a reversal, which could cost investors dearly, even more than a possible Eurozone breakup."

Yeah, except when exactly is that supposed to be happening? The U.S. economy has cooled recently, with disappointing job growth, and the Fed has promised to keep rates at record lows until 2014. In fact, just two weeks ago, Fontevecchia himself wrote a piece entitled "Brace Yourself For More Fed Easing In June, Goldman Sachs Says." If we're still talking about the Fed adding more stimulus, why should we be freaking out right now about the prospect of it eventually, at least two years from now, taking that stimulus away?

Betting against the bond market will almost certainly pay off one of these days. But it has been a losing bet for the past 30 years. And every time people step in front of the train -- as Bill Gross, chief investment officer of Pimco, the world's biggest bond-fund manager, did last year -- they get flattened.

In the meantime, the U.S. government will just keep borrowing money hand over fist at super low rates, thanks very much, defying the warnings repeated year after year that inflation and interest rates are going to explode any minute now. In fact, some could even ask why, with rates this low, the government hasn't been borrowing more to help stimulate the economy.