President Obama’s authorization of the assassination of an American citizen, New Mexico–born Anwar al-Awlaki—in a drone attack that also killed American citizen Samir Khan, who was raised in New York City and North Carolina—drew high praise from execution-enthusiast Rick Perry, who congratulated Obama by name for “getting another key terrorist.”

But the bipartisan disregard for the Constitution and the rule of law stopped when Texas Congressman Ron Paul was asked about the air strike that on Friday killed the two Americans in Yemen.

The congressman, who is competing with Perry and others for the 2012 Republican presidential nomination, has long complained about “war on terror” abuses that he sees as part of “the disintegration of American jurisprudence.”

And he was blunt in rejecting the victory-lap mentality that saw Obama Democrats and Perry Republicans celebrating the killing of American citizens.

“I don’t think that’s a good way to deal with our problems,” Paul said in New Hampshire. “Al-Awlaki was born here; he is an American citizen. He was never tried or charged for any crimes. Nobody knows if he killed anybody. We know he might have been associated with the underwear bomber. But if the American people accept this blindly and casually—that we now have an accepted practice of the president assassinating people who he thinks are bad guys—I think it’s sad.

Noting that no move was made to assassinate Oklahoma City bomber Timothy McVeigh, who was arrested, tried and executed, Paul said: “To start assassinating American citizens without charges, we should think very seriously about this.”

The congressman, who has been an outspoken critic on the expansion of the September 2001 Congressional authorization of a response to the attacks on the World Trade Center and the Pentagon to support a perpetual “war on terror,” said, “I voted to authority to go after those individuals responsible for 9/11. Nobody ever suggested that [Awlaki] was a participant in 9/11.”

Paul’s statement, and a slightly less pointed response from another libertarian-leaning presidential contender, reflects a more traditionalist view of the Constitution. As recently as the 1950s, “old-right” Republicans such as Ohio Senator Robert Taft and Nebraska Congressman Howard Buffett (Warren’s father) opposed undeclared wars and military adventures. Their stances extended from founding principles outlined by James Madison, when he warned that “no nation can preserve its freedom in the midst of continual warfare.”

It was a successor to Madison, John Quincy Adams, who warned against searching the globe for targets of assassination and military conquest.

“Wherever the standard of freedom and independence has been or shall be unfurled, there will [America’s] heart, her benedictions and her prayers be,” Adams told Congress in 1821. “But she goes not abroad, in search of monsters to destroy.”