If there's a US-Russia war by 2050, when will it start?

Another question in this tournament asks Will there be a US-Russia war by 2050?. This question asks more specifically when such a war will occur, if it does occur by 2050. Taken together, these questions can inform our views on:

• How much people today should prioritize reducing risks from nuclear war and certain other issues (such as possible biotechnology developments)

• Which interventions would be most effective (for example, specific diplomatic efforts in the near-term vs working more slowly towards more lasting policy changes)