President Obama attacked Libya in 2011 without congressional authority, and then shirked any responsibility to help stabilize the country after deposing its dictator.

By 2013, Libya had become a chaotic hellhole mired in a permanent war. Today it is a new beachhead and recruiting ground for the Islamic State.

Obama’s illegal, ill-considered, and immoral drive-by war in Libya ought to be a permanent stain on his presidency. The recent video of masked ISIS killers beheading 21 Egyptian Christians in Libya deserves to be the emblem of this president’s rash foreign policy.

“There is no overstating the chaos of post-Qaddafi Libya,” writes veteran war journalist Jon Lee Anderson in the New Yorker. “Two competing governments claim legitimacy. Armed militias roam the streets. The electricity is frequently out of service, and most business is at a standstill….”

Wars in Libya in the past year alone have taken about as many lives as 9/11 did. Those who can get out flee. Anderson reports that “nearly a third of the country’s population has fled across the border to Tunisia.”

The militants of the Islamic State are actually late arrivals to the “scumbag Woodstock” Libya has become, in the words a military contractor quoted by Daily Beast reporter Eli Lake. Ansar al-Sharia, a terrorist group connected to the deadly 2012 attacks in Benghazi, is already a staple there, along with at least three Al Qaeda affiliates, Lake reported last year.

Qaddafi was evil. But the lawless power vacuum he left may already be worse.

As we behold the horror of Libya, including this new Islamic State video, we need to remember the flippancy, deceit, and fecklessness with which the Obama administration helped lead the charge to regime change.

Only Congress has the authority to declare war. Federal law allows the president to conduct limited military actions in emergencies, and to continue them if he receives congressional authority. Candidate Obama stated in 2007, “The president does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation."

President Obama in 2011 never sought and never received congressional authority. His war was illegal by his own reckoning.

Deception was the norm in the early days of the attack. “The exit strategy will be executed this week,” Obama said in March 2011. We continued bombing for weeks. "We did not lead this," Secretary of State Hillary Clinton said. But a U.S. General and an admiral commanded the international effort.

Obama also never sought public approval. Unlike President George W. Bush’s invasion of Iraq, the Obama administration never made a public case for war. He probably understood that Americans had little appetite for another war in the Arab world — and one with very little conceivable American interest at stake.

That knowledge may have also motivated Obama’s decision to make Libya a drive-by war. “What I didn’t want,” Obama told reporter Michael Lewis, “is a month later a call from our allies saying, ‘It’s not working — you need to do more.’ So the question is: How can I cabin our commitment in a way that is useful?”

In other words, the only thing Obama learned from Iraq and Afghanistan seemed to be that nation-building is costly, difficult, and lengthy. He must have missed the lesson that the removal of one evil can open the door to greater ones.

Libyans tell CNN reporter Jomana Karadsheh that they feel America and our allies “did not really do enough to try and build a military, build a state.” We didn’t really “try and demobilize and disarm the militias in the aftermath of the revolution,” as Karadsheh put it.

At every stage, though, the administration behaved shamefully. Obama never tried to persuade Americans his war was just. He never sought the congressional action that would have made his war — sorry, his "kinetic military action" — legal. At one point, administration officials even floated the idea that they could frustrate the intent of the 1973 War Powers Resolution and its 60-day limit on unauthorized wars by momentarily stopping and then immediately restarting U.S. involvement. Obama never told the truth, perhaps for fear it would make his war more unpopular. And he never made the commitment to staying and rebuilding that could have made his war a success.

For some reason, Obama’s Libya war has received scant attention, both from his critics and from media commentators assessing his presidency. The people of Libya and surrounding countries, however, don’t have the luxury of ignoring the consequences.

Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at tcarney@washingtonexaminer.com. His column appears Sunday and Wednesday on washingtonexaminer.com.