Linkage was a foreign policy that was pursued by the United States and championed by Richard Nixon and Henry Kissinger in the 1970s détente, during the Cold War. The policy aimed to persuade the Soviet Union to co-operate in restraining revolutions in the Third World in return for concessions in nuclear and economic fields. Soviet interventions occurred in various conflicts such as the Angolan Civil War, the Mozambican Civil War, and the Ogaden War, while many revolutions still occurred in Third World countries, undermining the policy.

The premise behind linkage, as a policy, was to connect political and military issues. This established a relationship making progress in area "A" dependent on progress in area "B."

An important aspect of the policy was that deviations from respecting the rights and interests would be punished. The intent of this retaliatory action was to highlight to the offending state the limitations of acceptable international behaviour and demonstrate that attempts at expansion and upsetting international stability would not be accepted. This meant that conflict itself would contribute to stabilising the international order.

The Nixon-Kissinger approach did not link foreign and domestic areas.^{[citation needed]}

Selective relaxation of tensions is an opposing policy to linkage. In that case, an issue of arms control could be addressed and tension diminished, with the status quo being maintained in other strategic areas.

There have been different uses of the term ‘linkage’ in reference to both domestic and international policy making. There is often debate over the true meaning of the term. Historians and academics have portrayed the meaning of ‘linkage’ in different lights. Common understandings of the term are that linkage means leverage – the linking of one event to another in order to maintain bargaining power or pressure on the opposing party involved. Another description of linkage comes from Marvin Kalb and Bernard Kalb. They describe linkage as "an up-to-date application of [Henry] Kissinger’s theories about balance of power." Specific types of linkages can be coercive or cooperative. They can also be prospective, such as promises or threats, and they can be retrospective, such as rewards or retaliation.

Since the 1970s, the term has been used to make reference to the influence and manipulation of US-Soviet and east–west connections. An example of coercive linkage policy would be the US seeking to tie arms control progress to what they thought was acceptable behaviour in the Third World. This was based on the assumption that the Soviet Union wanted arms control more than the US did.

There are multiple theories behind linkage politics. The basic differences behind these theories are that the parties involved are either different or similar – with respect to their issue positions.