Aside from Afghanistan, NATO's relationship with Russia will dominate talks this weekend. NATO was set up largely to discourage an attack by the Soviets on the non-Communist nations of Western Europe. But since the fall of the iron curtain, the military alliance has been looking to expand eastward, to include former soviet states as members. Russia sees this push east towards its borders as a threat to its national security. The Bush adminstration added to the growing tension by pursuing plans to build a missile defence system in eastern europe. But now, Barack Obama is pursuing a new course with moscow.