THE DECISION of the United States Olympic Committee to accept the boycott idea should make it much easier for committees in other nations to join the protest. The Olympic Games without the participation of America's best athletes are just not the same. Victories in Moscow will be diminished in importance, and the question for winners, especially if they come from nations where the Olympics ideals are most deeply rooted, will not be "how did you win?" but "why did you go?"

That's why the Soviet press reacted so violently, almost comically, to the vote taken in Denver on Saturday. The Soviet government is trying desperately to salvage something from what was to have been a great public relations triumph.If athletes from other countries follow the lead of the Americans -- and there are indications quite a number may -- the Moscow Games will sink to relative obscurity.

Unfortunately, the USOC's House of Delegates did not take the second essential step. It voted overwhelmingly against the creation of an alternative competition next summer or fall in the United States or elesewhere. Such an alternative could have provided would-be Olympians with a showcase for their athletic prowess and laid the framework for an improvement in the international games.

The rejection of such an alternative seems to have come from the belief that, as USOC Executive Director F. Don Miller put it, there "is no substitute for the Olympic Games." No substitute exists because nobody has created one. If there is to be a truly international sports festival every four years in the future, the process of either creating some new event or reforming the present one should begin soon.

A wise IOC would now cancel or postpone the Moscow Games and examine carefully those of its own practices that made this year's events inevitable. A wise USOC would start pressing now for the needed changes, including a permanent site for the Games, or looking for that substitute. The boycott is not an aberration. It is the sign of a severe, most likely fatal, ailment.