Admiral Mike Mullen told students at the Naval War College there were no plans to dispatch troops to Yemen because it is a sovereign nation and the United States doesn’t send troops into other countries because it feels like doing so. I am glad to learn the United States of America does not send troops into sovereign nations without being invited. Of course, Iraq was a sovereign nation and shortly discovered the presence of over a 100,000 Americans in their countryside and they were shooting guns and dropping bombs. Perhaps, there is now a Mullen Doctrine which is based on the proposition that American troops will never enter another nation without a formal invitation.
It might have even been better news for the naval students to learn the United States was not dispatching any troops to the sovereign nation of Afghanistan. How about expanding the Mullen Doctrine to include no US troops except in the United States?