[RWebb]

There are two problems - if we don't do it then the lens and computer parts (it is a spy sat) could survive intact, compromising our spying ability.

If we do shoot it down, then everyone will be sure to watch very very carefully, compromising the secrecy of our ground-based ASAT capability.

I doubt this is a signal to China or whomever.

It is also unclear how much hydrazine would survive re-entry. It may be just a red herring.

My bet: we "miss" with the SM-3 missile, but -- oddly -- it somehow fragments and burns up anyway.