One of the nicer things American diplomats say about Saddam Hussein these days is that we should pay more attention to what he does than what he says.

Not surprisingly, this saying has become something of a mantra here in Washington since the U.N. secretary-general, Kofi Annan, cut a deal with Hussein last month on inspecting Iraq's suspected chemical and biological weapons sites.You don't have to be a genius to figure out that what the diplomats mean to say about Saddam is that he doesn't always do what he says he's going to do; that if you expect the Iraqi leader to keep his word on something, you have to check up on him, get in his face and annoy him now and then.

Maybe it's in this spirit that we can best understand Annan's visit to Washington this week. We've told the U.N. chief over and over that we intend to pay the $1.3 billion Washington owes the United Nations in back dues, but we still haven't paid up.

So now Annan is visiting Washington to get in our face, to annoy us a bit, to say, "A deal is a deal. Where's the money?"

On the outside chance that President Clinton or anybody else here might miss the point, Annan wrote a long article for the New York Times the other day spelling out all the reasons Washington needs to get up to speed with its U.N. dues.

Then he followed that up by telling reporters that he was moving ahead with a program to slim down the U.N. bureaucracy as demanded by Washington so now it was time for Washington to come through on its part of the bargain.

"We have delivered and I want to know when they will deliver," Annan said.

And just in case even that bit of diplomatic bluntness might prove too subtle for some of the harder-headed U.N.-bashers in Congress, Annan had the chief U.N. financial official warn that Washington risks losing its voting rights in the U.N. General Assembly if it doesn't pay up soon. That's the penalty for nonpayment spelled out in the U.N. Charter, noted Joseph Connor, who happens to be an American.

For a soft-spoken guy like Annan, this is exceptionally rough stuff, the equivalent of putting a pistol on the table during a poker game. He may be descended from a line of Ashanti royalty in West Africa, but Annan is coming across on this dues collection business with all the chutzpah of a native New Yorker.

This, in any case, was the backdrop of Annan's meeting with Clinton at the White House on Wednesday and his session later in the day with Sen. Jesse Helms, R-N.C., chairman of the Senate Foreign Relations Committee. Annan was saying that it was time for the White House and Congress to sort out their differences and make good on America's promises.

As he put it to reporters earlier in the day, Clinton needs to "come out a bit more aggressively and work with Congress in getting the money."

That may be so, but Annan is also well aware of the problem Clinton faces on U.N. dues: Conservative Republicans in Congress have stipulated that any back dues payments Washington might make can't be used in any U.N. program that advocates or funds abortions anywhere in the world.

Indeed, conservative anti-abortion amendments are what killed a deal to pay up $800 million in back U.N. dues last year. Under that deal, by the way, when Washington got current on its U.N. dues, its rate of dues assessment would have dropped from 25 percent of the U.N. budget to 22 percent. So by not paying up, Washington was actually losing money over the long run.

But even this kind of basic arithmetic didn't seem to impress the anti-abortion people in Congress. Even as Annan was flying into Washington on Wednesday, a group of conservative Republicans in the House of Representatives announced they would once again tack on anti-abortion language to any attempt to pay back U.N. dues this year.

It's worth talking about this unpleasantness now because the Clinton administration is becoming ever more reliant on the United Nations to help carry out its foreign policy. Indeed, its entire policy toward Iraq hinges on a highly cooperative, if not compliant, United Nations.

That why Annan's message to the White House and Congress on Wednesday was stark and simple: If you want me to do your job with Saddam in Baghdad, you've got to help me out in Washington.

It's hard to argue with that kind of logic, especially when the White House and leading members of Congress agree that Annan is doing his best to trim down the U.N. bureaucracy in New York.