TAX BREAKS FOR the middle class. A balanced federal budget in the next century. Limits on the growth of federal spending. That's what the voters want, the pols say. We should act quickly.

Few dare to question the new mantra. A rare skeptic, Laura Tyson, chair of President Clinton's Council of Economic Advisers, suggests that the "discipline of the markets" might alter these plans. But her voice is all but lost as the mighty host raised by incoming House Speaker Newt Gingrich girds for a "revolution."Lost in the buzz over the need to cap the annual deficit, which is running in the $200 billion range, is the mountainous national debt, which now stands at some $4.5 trillion. Even with a flawed Pentium computer chip, it's easy to see that this has put every American in hock to the tune of about $17,500.

During the go-go decade of the 1980s, things seemed to work out when, as a nation, we borrowed $3 trillion to finance our spiraling debts. It was sure nice that one in five of these borrowed dollars came from the wallets of overseas investors.

Insiders worry that this sweet deal is about to end. If it does, the first victim would be the U.S. dollar, which would collapse in value. The next victim would be the U.S. economy, which in turn would harm most every American. If such events come to pass, the current puffed-up talk about cutting taxes would soon be left behind as a hollow diversion.

As the year ends, there's no shortage of warnings. Watch, for example, what happens in the week between Christmas and New Year's Day, when the Treasury goes into the market to refinance $22.8 billion in maturing short-term debt. Since the U.S. money machine must be fed an ever-richer diet, the Treasury will be selling $26 billion in new paper.

This time around, foreign bankers won't be so eager to buy. To be sure, the government will get the cash it needs to do its business. But each time, it - sorry, we - will have to pay more than if the foreigners were still bellying up in the casino.

The reasons for the overseas reticence aren't hard to fathom. First, since the early 1980s, many more chances have opened up to make money in other places, such as Asia.

Second, since the early 1980s, the dollar has plunged in value against the Japanese yen and other strong currencies. The Japanese, who now control three-fifths of the world's surplus capital, aren't at all pleased to see the bonds that they bought when the yen stood at 240 to the dollar being redeemed at less than 100 yen to the dollar.

Third, and most crucial, the United States has become the world's largest borrower. Having your hand out all the time doesn't buy much respect from lenders, no matter how many guns you may have stowed away in the attic.

Six times this year, the Federal Reserve raised interest rates. It will probably do so again early in 1995, thereby casting a further shadow over the U.S. economy.

Nearly everyone says the Fed has done this to curb the threat of inflation. But they may be wrong. Smart money managers know that, in reality, Fed is trying protect the dollar from a big hit in what, in the end, could well turn out be losing effort to overcome our past mistakes.