May I please attempt to inject some common sense into this discussion?
The suggestion of using T-X for home defence is somewhat akin to the decades old plan of using Hawk T1s with AIM-9 for UKAD.
Yes, there is a capability and yes the T-X could strap on some missiles and shoot them at people in extremis.
The proposed T-X design is a great jet and has great performance. For a trainer.
If the USA is ever in a position where it is relying on Squadrons of T-X’s for Homeland defence then yes it may prove useful. There would have to have been a few thousand combat losses of F22s, F35s, F16s, F15s and F18s before that ever became reality though.
Whilst the T-X could almost certainly beat some old jets (ie MiG 15/17 maybe even 21) it would quickly find itself embarrassed in a fight against any actual fighter (ie the Flanker series).
With all this said, please remember the specification for T-X was for avionics that emulate modern frontline capability. That does not mean it will, or could, ever have an actual Radar.
My final point is that I have noticed a recent trend for individuals with an obvious dearth of knowledge to start posting on military topics about which they clearly have no actual credentials. Experience of PlayStation or a subscription to Airforces Monthly does not make you an expert.
Now please, use your extensive knowledge and experience to shoot me down.
BV