I'm not making a general argument about how laws are enforced in DC.
You and I were discussing whether the deployment of US forces against the bonus army was a violation of the posse comitatus act.
Since it's a statute passed by Congress, and within it has provisions for Congress to authorize force when it deems fit, then we can either try and construct a legal argument about the legitimacy of mobilizing federal forces in a federal district *or* we can dig through the congressional records to see if they passed a bill on the way out the door authorizing the use of federal force to protect them from the vets marching on them.
Either way you want to do it, I think we can safely conclude that in regards to the bonus army marches, the use of federal troops to protect congress was legal