Linked below is the text of a letter written to Governor Greg Abbott
by (then) University of Texas Chancellor William McCraven.  Chancellor
McCraven is a 4-Star Admiral (Retired) from the US Navy.
He is former Navy Seal and Commander of US Special Operations. 
He orchestrated the raid that killed Osama Bin Laden.  Read his
biographical notes from UT by clicking Here

It seems to me that regardless of the opinion anyone takes on this
matter, Admiral McCraven's credibility and experience make his
insights worthy of respect.

Here is his Letter