In this case I think energy weapons will provide better defense than force projection. You will be able to defend at near the speed of light within X amount of miles, but you will only be able to project massive force through vastly slower moving missiles.

So the physics does suggest eventually nukes become less important/dangerous as faster but more limited range defense becomes more viable.

Sure people will make counter-measures for energy weapons, but because the fundamental laws of the universe appears on the side of shorter ranger super fast weapons being possible, but not super fast longer range weapons being possible there is a big opening there for missile defense to outstrip missiles.

A similar thing happened to bombers. You can make them stealth and all, but ICBMs made huge armies of bombers much less practical and they never overcame that problem. SAMs also makes projecting air force a lot harder because basically missiles are a lot easier and cheaper to make than high end jets.

Another option will be stealth missiles, but the speed of electromagnetism will always work against those options and eventually probably overcome them. Just like now it's hard to launch a nuke and not have alarms go off, the problems of needing massive energy release to accelerate mass quickly will keep working against missiles vs energy weapons.

We just can't see this yet because energy weapons are immature.