Can the US Government Assassinate a US Citizen?

The legal analysis, in essence, concluded that Mr. Awlaki could be legally killed, if it was not feasible to capture him, because intelligence agencies said he was taking part in the war between the United States and Al Qaeda and posed a significant threat to Americans, as well as because Yemeni authorities were unable or unwilling to stop him.
Excerpt of article by Charlie Savage, Secret U.S. Memo Made Legal Case to Kill a Citizen, NYT, 10-9-11

The specifics are not available for a proper review and conclusion therefore well-founded stands on the issue remain tenuous, at best.

There is little room for doubt in establishing that Anwar al-Awlaki was sympathetic to the cause of radical Islam. It is also clear that he was vocal in justifying its violence and encouraging the support for jihad. What remains uncertain is what exactly he did that went beyond the protections of the 1st Amendment. Can we prove that he was linked to and participated in terrorist operations? If captured, was there sufficient evidence to try him for treason? Was he, in fact, an enemy combatant?

The Constitutional criterion for proving a citizen guilty of treason is strict. The US Supreme Court has established that “Conspiracy short of the actual levying of war is insufficient”. Treason also requires the testimony of two witnesses with direct knowledge of the treasonous actions carried out by the accused. Historically, most Americans that were convicted of treason were not put to death. Our traditions have always looked to protect individual rights and freedoms. Our government must tread very carefully when dealing with a citizen. Unfortunately that standard has been violated repeatedly in the recent past. Even the media and commentary shows aggressively put forth the arguments supporting conviction in news events where the accused is still innocent and not yet convicted of the alleged crime.

The only other issue that seems relevant in the al-Awlaki case is that of dual citizenship. While our judicial system presumes loyalty to the United States exclusively it does not account for loyalty elsewhere. We must consider eliminating this by revoking US citizenship to any citizen who has accepted or retained citizenship in another country. Nevertheless, this is not directly relevant to the argument on whether the federal government was justified in killing al-Awlaki.

The only justification lies in proving that al-Awlaki was directly involved in the planning and execution of terrorist acts. For now, we do not know because the entire process that led to his assassination is hidden behind a wall of secrecy. If we are subjected to only believing what the government assures us is the truth we will have surrendered our freedoms and subjected ourselves to the dictates of politicians and bureaucrats. The worst aspect of this is that it is tantamount to a total disregard for the Constitution and the rule of law.