On January 25, 1984, in his annual State of the Union address to a joint session of Congress, President Ronald Reagan announced that "tonight, I am directing NASA to develop a permanently manned space station and to do it within the decade." A few moments later, he added: "We want our friends to help us meet these challenges and share in their benefits. NASA will invite other countries to participate so we can strengthen peace, build prosperity, and expand freedom for all who share our goals." Just over a year later, during the April-June 1985 period, Canada, Japan, and Europe accepted in principle the U.S. invitation to participate in the space station program. Thus was initiated the most extensive experiment in international technical cooperation ever undertaken. This essay is a history and analysis of the steps leading to the origins of the space station partnership between the United States and its closest allies. It traces the process that led to the decision to invite other countries to participate in the project and their reasons for accepting that invitation. Not covered in this account are the difficult negotiations during the 1984-1988 period that led first to an initial set of agreements that allowed the prospective partners to work together during the early stages of the space station program and then to the final set of agreements creating the original space station partnership. Also, the 1993 invitation to the Russian Federation to join the original partners is not discussed, nor are the subsequent negotiations to revise the 1988 agreements.