By lowering interest rates this week in an effort to breathe life into the ailing American economy, the Federal Reserve Board is taking a calculated risk.

If all goes well, the lower interest rates should spur the economy by making it easier for consumers to buy such expensive items as cars and houses and by making it easier for businesses to build new plants, hire new workers and expand.The risk, though, is that foreign investors may withdraw their money from the United States and put it to work in other countries offering a higher return. If that happens, the United States will lose foreign money it has been using to help finance the big and stubborn federal deficit.

All things considered, the Fed's gamble looks reasonably prudent.

After all, the cut in the discount rate that the Fed charges member banks for loans - the third such cut in four months - comes at a time when inflation seems to be under control.

Much more encouraging is the track record of such Fed moves. Each of the six occasions since world War II that the Fed has cut the rate at least three times within a few months, the stock market has rallied significantly over the next year.

Even so, Washington still faces a big challenge. It is to get other major industrial nations to follow the Fed's lead and cut interest rates, too.

So far such nations are resisting. But there seem to be limits to how long they can hold out. Britain, Canada and France are following the United States into a recession. Meanwhile, growth in Japan and Germany is slowing. If the trend continues, eventually the economies of poorer nations - which depend on global markets - will suffer, too.

The message to the major industrial nations is unmistakably clear: Follow the example of the United States and cut your interest rates, too, or much of the world could be drawn into a recession.