Full Idea
There is no reason why we cannot stipulate that, in talking about what would have happened to Nixon in a certain counterfactual situation, we are talking about what would have happened to HIM.
Gist of Idea
If we discuss what might have happened to Nixon, we stipulate that it is about Nixon
Source
Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
Book Reference
Kripke,Saul: 'Naming and Necessity' [Blackwell 1980], p.44
A Reaction
For many people (including me now, I think) this lays to rest the supposed problem of 'transworld identity' wrestled with by Kaplan and Lewis.