Why is the Nuclear Triad needed if nuclear subs can’t be realistically countered?

Question

Why is the Nuclear Triad needed if nuclear subs can’t be realistically countered?

In: Technology

Answer 1

Making a nuke at all: hard as shit

Making one that a plane can carry: a decent bit harder but not that much

Making one that fits on the tip of a rocket: WAY fucking harder

Making a rocket that can carry a nuke but is small enough that the whole rocket fits inside a submarine which is also nuclear so now you need a nuclear reactor small enough to fit inside that same submarine: Dude…

Basically every country that can field nuclear subs will have already made nuclear bomber planes and nuclear missiles before then, because those are way easier. But France used to have a complete triad and only later they got rid of their land-based missiles and kept only bomber and subs, so clearly they do share your line of thinking to some extent.