A RIOT of sculpture has spilled out of Washington's Museum of Modern Art of Latin America and over the grounds of the Organization of American States. No resistance is possible.

Fifty-two (!) artists are represented in the show, which is arresting passersby on Constitution Avenue and pulling tourists off the Mall. The exhibit is the largest and most exuberant of this summer's citywide shows celebrating "International Sculpture '90."

The scope of the Latin American show is so broad that all the artists can be said to have in common is they are all living and they're all living in the Western Hemisphere. For the first time since its founding, the museum has chosen to include artists from the United States and Canada.

For every cool abstraction there is a "statement" sculpture committed in hot blood, and the constant switching of sensibilities adds to the exhilaration. Many of the works are scattered through a grove of shade trees along the corner of 18th and Constitution NW, creating witty -- or startling -- encounters with unsuspecting strollers.

SCULPTURE OF THE AMERICAS INTO THE NINETIES --

Through Sept. 8 at the Museum of Modern Art of Latin America, 201 18th St. NW. 458-6016. Open 10 to 5 Tuesday through Saturday. No wheelchair access to the building, but the grounds have paved paths.