Drone Strikes

Is it ever appropriate for the U.S. government to kill one of its own citizens without providing them with a constitutional due process of protections?  I believe it is appropriate if an individual is a risk to innocent lives. For instance if an Al-Qa'ida member receives his citizenship and is a citizen for a number of years and then is plotting an act of terrorism and is taken out by an American drone before he is able carry out this act of terrorism, then the government is doing its job in protecting its citizens.  If the government were to wait and attempt to prosecute this individual he may be out of the country before he is found.  This forces the government to send troops to where this individual is hiding, putting American soldier's lives at risk, and in some cases losing troops to catch an individual who we could have got on American soil.  Once the terrorist is captured, given a trial, and placed on an island to live out the rest of his life.  I do not however believe that killing citizens who are not plotting acts of terrorism or are not a risk to hundreds or thousands of American lives is right or just.  Drone attacks on American citizens is merely self defence carried out by the government(on individuals who are a threat to innocent lives). Article