Kripke's Meter-Stick If the actual world determines everything, then all actual states of affairs would be necessary truths. But we can still speak of counterfactuals somehow, right?
“Nixon” is a rigid designator so we know who we are talking about in other stipulated possible worlds. It’s a contingent truth that he was president because we can logically conceive of him not being president. It’s a necessary truth that he is not a cow, for example. We wouldn’t be talking about Nixon then.
We can logically conceive of him being called “Smith” in a possible world that he was adopted. However, “Nixon” is still a rigid designator because that is how we know we are talking about the same person. It’s a rigid designator, but that name given to him is a contingent truth.