If we shot down the TD2, or caused it to malfunction, I doubt it was with a SM-3 because too many other countries would have detected and observed that. Now, depending on where the test-bed 747 HE ABL was, that renmains a possibility because it would have been much more difficult to detect.
If we had a part in it, we probably would not reveal our hand in any case...leave them guessing and wondering.
If it failed on its own...all the better.
I wonder if sitting on the pad fueled for over a week was a factor. That liquid fuel is pretty corrosive. Too bad it didn't blow up on the pad and take out the whole facility.
How could we protect our allies with a missle defense if we did not use the interceptor system right away. It takes a while for our missles to get to theirs before its too late.