The Constitution doesn't forbid the sitting President of the United States to give orders. In fact, the Constitution stipulates that the President shall be the Commander in Chief. That means he can give orders. Obama is the sitting President of the United States no matter how much we don't like him.
The Constitution stipulates that before entering upon the execution of his office, the President-elect shall take an oath and that oath is dictated word for word by the Constitution. Obama took that oath, twice, as it was administered by Chief Justice John Roberts. Therefore, Obama entered upon the execution of his office as the sitting President of the United States.
If he is later found to have been ineligible for the office, the Congress can impeach, convict and remove him from office or he can resign. Short of that, he is and remains the sitting President of the United States and all branches of our government are operating under that legal conclusion.
The virtual stomping of feet and temper tantrums by some insisting that Obama is not the sitting President don't do anything to advance the eligibility question. As jamese777 repeatedly points out, a grand jury can compel testimony and document production to investigate ANY potential crime about which they have personal knowledge, even if the District Attorney objects. Go present your evidence to a legally empaneled grand jury when they are in session. You can catch them on them outside the courthouse and hand them a prepared docum I ent explaining the highlights of your arguments. Better yet, apply to serve as a grand jury member. I did and I'm on the list waiting to be called.
It doesn't forbid a CONSTITUTIONALLY ELIGIBLE POTUS from giving orders. You need to think this through before you post, chief.