The podcast cover the following factors:
Economic > the financial benefits of reducing arms expenditure for a US drained by the Vietnam War and for a USSR that faced a stalled economy and weak satellite states.
Military > both countries were deeply aware of their nuclear capabilities (MAD: mutually assured destruction), and having achieved parity, were more prepared to discuss arms limitation.
Politically > (a) the US potential gain from the Sino–Soviet split by fostering separate relationships with both countries whilst driving them further apart;
Politically > (b) the Soviet wish to secure American recognition of the post-war borders of its satellite states;
Politically > (c) the impact of Ostpolitik which had relaxed tension in Europe and encouraged trade.