Other than the cost, some people opposed SDI because It might put weapons in space. The Strategic Defence Initiative was opposed as it threatened to inflict damages on the relationship between the United States and the Soviet Union. The technologies central to SDI were exotic as they had laser and other directed energy weapons, space-based tracking, and battle management systems which were difficult to assess which resulted in uncertainties in the SDI issue. The reaction of the Soviet Union further triggered opposition to the SDI as it was unknown while how the technology would develop. The other concern was how future presidents and Congressmen would respond to Reagan's vision and initiative.