My comment was limited to radiant energy weapons. As to those, the critical vulnerability exists during launch and boost phase. The target is slow, bright, large, has fuel on board and a nonarmored hull, which (as other posters observed) can be weakened with enough flux.
At least one of the propaganda articles said the kill mechanism was to make a hole in the hull near the fuel tank. High albedo may help the missile here as well as the warhead, though it's probably harder to deploy decoys at launch and boost phase than re-entry.
The demos are just that: demos. Given that a limited strike is best conducted with remotely operated civilian aircraft, or plain old UPS, star wars seems like effect of industrial lobby.
The primary purpose of demos is to create public pressure
to get increased funding, plus to remind the public that we still have a
nuclear-war-industrial-complex that's Protecting Our Country Against Somebody,
so in case EastAsia ever becomes a credible threat to Oceania,
Our Brave Military will have the infrastructure to do something about it.
Meanwhile of course, any foreign terrorist that wants to nuke the US
with a physically small weapon only needs to pack it in cocaine
and bring it in with the regular shipments,
while Rogue Nations that can only make large Fat Boy style weapons
need cruder methods, like bribing a crane operator to load the wrong
container on a ship bound for New York or Los Angelese harbor.
X-Authenticated-User: idiom
~~~
Thanks;
Bill Stewart