Eighteen years after withdrawing in a huff, the United States is rejoining the United Nations Educational, Scientific and Cultural Organization. The move, announced by U.S. President George W. Bush in his recent U.N. speech, is a victory for the world and for Mr. Koichiro Matsuura, the Japanese diplomat who heads the world body.

UNESCO's importance has grown in parallel with concerns about the possibility of a "clash of civilizations" in the wake of the war against terrorism. The organization was founded in 1945 "to advance human rights, tolerance, and learning." The U.S., a founding member that once supplied a quarter of its annual budget, withdrew in the 1980s, along with Britain and Singapore, in protest over corruption, politicization and mismanagement.

Mr. Matsuura took over the institution in 1999, vowing to focus the organization on core concerns and to clean up its management. Those efforts were noted by Mr. Bush, who explained that UNESCO "has been reformed and America will participate fully in its mission to advance human rights, tolerance, and learning."