The threat that the Soviet Union poses to Western access to Persian Gulf oil encompasses several levels. On one level, there is a military threat of invasion and occupation of one or more oil-producing countries. The former buffer state of Afghanistan is now under Soviet control. The USSR's borders are contiguous with Iran and, in effect, Pakistan. On another level, there is the threat of subversion, of active interference in a country's internal politics to weaken it and make it susceptible to Soviet influence. The network of Communist parties maintained throughout the Middle East and support of discontented ethnic groups are examples. On a third level, the Soviet threat consists of Moscow's ability to exploit purely internal developments. The paper analyzes Soviet policy towards the Persian Gulf, describes Soviet objectives in four key countries and the general problem of intervention from a Soviet perspective, and gives implications for U.S. and allied policy.