[mytailorisrich]

Not necessarily.

Dissuasion must be credible and that requires credible delivery systems (missiles).

Thus, if for example the US develop anti-missile systems that are able to shoot down Russian missiles then Russia no longer has a credible dissuasive arsenal. Consequently Russia must develop new missiles that evade anti-missile systems. This does not mean that they are designed for first strikes, it just tells the US "don't hit us because we can really still hit you back".

It's the age old race between offensive and defensive systems.