State of the Union speeches, if they're as good as President Reagan's was, are poetry. Budgets are prose -- or, worse, numbers.

State of the Unions are where you showcase everything that's going right, everything you hope to accomplish. Budgets are where you sometimes have to confess that things are off-track.

But not up-front. There's nothing in the Constitution that requires a president to advertise calamity. So Reagan, like his predecessors, hid it away, deep in the thickets of the budget document he put out last week.

Half of the scare story was tucked away in a table on page 157 of Chapter 5 of the budget. The other half appears nowhere; you have to go into the past records to find it for yourself.

I'm going to put down a series of numbers for you to look at: 32.3; 36.7; 49.5; 65.8; 67.6; 111.1. Here are four more: 130.4; 142.6; 152.9; 159.2.

I'm not trying to be mysterious. The numbers measure the annual interest payments on the national debt. Put a dollar sign in front of them. Put a billion behind them. What they describe is a runaway locomotive.

The first six numbers, running up from $32 billion to $111 billion, represent the actual increase in the annual interest payment between 1979 and 1984. (Only the last number is included in Reagan's budget.) It's more than tripled.

The next four numbers, jumping from $130 billion to $159 billion, are Reagan's projection of the annual interest payments in the next four years.

Note two things: first, the rate of increase slows, because Reagan's budget assumes that "the 91-day Treasury bill rate (a key to the rate of interest the government pays) will decline steadily from an average of 9.6 percent in calendar year 1984 to 5.9 percent in 1988." Set aside that blue-sky forecast and annual interest payments zoom to the $200 billion range.

Note, too, that even under Reagan's optimistic forecast, annual interest payments will have quintupled -- multiplied by five -- in 10 years.

And they will continue to soar because under Reagan's budget, if every single one of his savings proposals is accepted by Congress (fat chance!) he would have us increase the federal deficit by $144 billion in 1988 and add proportionally to the annual interest bill.

The point is not complicated; it's just one Reagan wants to keep secret: The deficit is eating us alive; it's running away with us. And it can't be cured on the spending side, even if you swallow all Reagan's medicine.

This is no big discovery on my part. Last September, Sen. Daniel P. Moynihan (D-N.Y.) wrote that, "The interest deficit has begun to go out of control. In 1980, the Treasury spent $52 billion in interest payments. This year, the bill will reach $111 billion. By 1989, $214 billion. . . . What Lord Keynes called the 'magic of compound interest' works with debt as well as with savings. It starts slowly, then explodes."

That explosion is now happening. It will occur whatever Congress does with Reagan's proposed budget cuts -- even if Congress accepts them all.

It will go on until it ravages the value of the dollar, unless -- unless someone has the courage to say we have to pay for the amount of government services we get. Unless someone says, "Raise taxes."

Reagan won't, because he promised not to. The Democrats won't, because Walter Mondale did, and he lost 49 states. I am a political reporter, and I understand political realities. But I can also add and subtract. And since I'm not running for anything, I can tell you what the politicians won't: taxes have to go up.

The president's Council of Economic Advisers hinted at the truth in its report last week. The Wall Street Journal editorialists caught Sen. Bob Packwood (R- Ore.), chairman of the Senate Finance Committee, suggesting it might be necessary to raise taxes and promptly warned him, "We'll be watching."

If the cost of a weapons system or a welfare program were quintupling, everyone would say it was out of control. But interest payments are quintupling in a decade -- and almost every politician looks the other way.

Why? Because they think the people will not accept tax hikes. That's a strange assumption. Hidden away in Reagan's budget is a table showing the tax hike Congress passed in 1982 (in partial penance for the tax-cut orgy of 1981) brought in $36 billion in 1984 and will bring in $254 billion between 1984 and 1988. The 1984 tax bill will add $72 billion more in receipts.

Did those tax hikes unleash a flood of new spending proposals? Did they abort the recovery, diminish investment incentives, trigger a taxpayer revolt or destroy the American way of life? Hell no; they just reduced the hemmorhage of red ink.

But Reagan says taxes must not be raised, and Reagan won 49 states, so that settles the matter.

We have a president who believes in traditional values. All but one: he doesn't believe in paying his bills. And the Democrats are too scared to challenge him.

Our kids will pay for this folly.