Ya know, you're right. If I am to remain, it's important that I give your ideas serious consideration, and contribute to the thread at the level of discourse that you've established with your own posts.
So...
I once saw a Japanese monster movie, where the hero robot programmed itself to "get big", and suddenly grew from man-sized to Godzilla-sized. The now giant hero robot then saved Tokyo from a missile attack, simply by snatching the missiles out of the sky with its hands.
Now, even though programing doesn't work that way...yet, and giant, Godzilla-sized robots do not exist...yet, what do you think the chances are of using some variation of this idea in the near future to achieve the sort of Nuclear Defence that our esteemed OP desires?
What changes to this giant robot scenario could be made that would make the idea more practical? (A giant Robot-sized catcher's mitt perhaps?)
How much do you think it would cost?
What color should it be?
Should it be able to transform into a cruise ship sized submarine, or maintain a fixed robotic state?