The troops gathered last night for yet another USO show.The scene wasn't Korea or Germany but the Sylvan Theater and this time out, the ranks were filled with tourists and Washingtonians who has assembled for the organization's 40th birthday celebration.

Of course, no USO show would be complete without Bob Hope. The great, graying eminence of servicemen's comedy put in a brief appearance tossing from the noisy jets at National Airport to the president. Referring to Reagan, Hope said, "He's the greatest thing for Hollywood since George Burns made God."

Local television personality Henry Tenenbaum hosted the event, which included performances by The Crown Beauties of Soul, and the Catholic University USO troop's show, "Shinin' On." Miss America, Susan Powell, presented several light operatic selections and eight of the Dallas Cowboys Cheerleaders topped the proceedings, singing, dancing and shaking their pom poms.

Each of the performers took time out to salute the 40,000 USO volunteers who donate their time and talents to entertain and assist more than 5 million servicemen and their families.

At the end of the show, the cast joined hands on stage for a quiet rendition of "America, the Beautiful." The entire crowd stood and sang, the massed voices echoing off the Washington Monument.It was a fitting moment that captured the spirit of the USO, the troops it serves and the country it represents.