Last week's targeted killing of the fiery American cleric Anwar al-Awlaki raises questions about the appropriate use of force in the war against terrorism.

Is it really legal for the CIA to kill U.S. citizens without the due process afforded by the courts?

What precedent is established through such actions?

What does this say about the United States as a nation?

The Hellfire missile launched Friday morning by a Joint Special Operations Command drone hovering high in the Yemeni sky took the lives of two Americans -- Awlaki and Samir Khan. The due process afforded the men was limited to a legal memorandum penned by the Department of Justice and approved by the Obama White House. CIA officials at Langley headquarters reportedly undertook supervision of the strike.

It's not altogether surprising that, after a decade of counter-terrorism operations directed at foreign nationals, the targeting of a U.S. citizen stirred a fierce domestic debate about what constitutes an appropriate and legal target.

Days later, questions linger: Can the U.S. government target its own citizens? Does the maneuver constitute a shift in policy? What next?

To be clear, Awlaki and his American co-conspirator, the editor of a Web-based al-Qaida magazine, hardly cut a sympathetic profile. Both had been in the U.S. cross hairs for some time and both had ample opportunity to abandon their calls to jihad.

But the CIA as judge, jury and executioner of U.S. citizens who are deemed a threat establishes a dangerous precedent and raises concerns of a constitutional nature. These concerns should be addressed by the Harvard-educated lawyer and former constitutional law professor who sits in the White House and approved the hit.

In the fury of activity following the kill, one Department of Justice official was said to have commented, "What constitutes due process in this case is what constitutes due process in war." There was reportedly little disagreement as to whether such actions were allowable under U.S. law. But what about protections guaranteed by the Constitution? For that matter, what about resolutions passed by the U.S. Congress and international provisions against assassination. Do any make allowances for the addition of Americans to kill-lists? Under what circumstances?

The questions coming U.S. President Barack Obama's way are certain to be challenging ones: Who decides which Americans will be tried under U.S. law and which ones will be cut down in the street? How elaborate will these judicial reviews be and who will conduct them? What considerations, if not the law, will go into the decisions to target Americans? Will such hits take place on U.S. soil? What about the dispassionate system of justice that supposedly sets the U.S. apart from those who make decisions to kill based on arbitrary criteria?

The questions will likely raise the ire of White House lawyers forced to respond to this check on presidential power. It's worth noting, however, that few concerns were raised as the Obama national security team approved a massive escalation of drone strikes over the past two years. In fact, unmanned aerial vehicles have become the most tangible symbol of the shift in U.S. counter-terrorism strategy under Obama, a president who campaigned against what he termed "dumb wars" in 2008.

By some estimates, Obama presided over the launch of more than four times the number of drone attacks during the first half of his first term than President George W. Bush ordered in eight years in office.

That the drones, with names like "Predator" and carrying rockets called "Hellfire," have resulted in untold civilian casualties seems not to be of concern. The United States maintains a fleet of more than 7,000 drones and the Pentagon is reported to have asked Congress for an additional $5 billion for the vehicles in 2012.

The mass violence inflicted via drones on non-Americans in Pakistan, Afghanistan, Yemen, Somalia, and other weak and failing states raises moral and tactical questions about the calibration of U.S. counter-terrorism efforts.

History will judge whether this use of violence was justified, legal and effective. But the killing of Americans without due process, however justified, expedient and seemingly necessary, raises immediate legal concerns. The laws that were either pushed aside or used to justify the decision to target Awlaki should be made clear and the decisions by Justice Department and White House officials should be investigated. Congress should take a prominent and active role in this investigation and the implications of continuing along this slippery path should be considered.

John Brennan, the president's chief counter-terrorism adviser, may well be justified in celebrating Awlaki's kill and Obama may be correct in calling the strike a "milestone." But when the celebrations die down, the incident is sure to raise as many questions as cheers. Americans will next need to decide whether such violence is legal and under what circumstances they can be targeted by their own government.

(Ivan Sascha Sheehan is the director of the graduate program in Negotiation and Conflict Management in the School of Public and International Affairs at the University of Baltimore. The opinions expressed are his own.)

(United Press International's "Outside View" commentaries are written by outside contributors who specialize in a variety of important issues. The views expressed do not necessarily reflect those of United Press International. In the interests of creating an open forum, original submissions are invited.)