“President Obama has arguably established the authority of the president to intervene militarily virtually anywhere without the consent or the approval of Congress, at his own discretion and for as long as he wishes.” — Jim Webb

As America tiptoes toward a fourth intervention in an opaque and uncontrollable conflict — now Syria, after Iraq, Afghanistan and Libya — Webb’s words require two minor modifications: Obama has demonstrated a power, not an authority; only the Constitution authorizes. And as Webb understands, Obama has been able to do so only because Congress has become too supine to wield its constitutional powers.

Webb, a Virginia Democrat who declined to seek a second Senate term, vents his dismay in the essay “Congressional Abdication” (in The National Interest), a trenchant indictment of the irrelevance of an institution to which the Constitution gives “certain powers over the structure and use of the military.” The president, Webb says, is commander in chief but only in “executing policies shepherded within the boundaries of legislative powers.” Those powers have, however, atrophied from a disuse amounting to institutional malfeasance as Congress has forfeited its role in national-security policymaking.

Webb, a Marine infantry officer in Vietnam and Navy secretary for Ronald Reagan, remembers when Congress was “fiercely protective of its powers.” Webb vigorously opposed the invasion of Iraq before he entered the Senate, which he departed disgusted by Congress’ self-made irrelevance.

In December 2008, in its final hours, George W. Bush’s administration signed with Iraq a Strategic Framework Agreement that was, Webb says, “not quite a treaty” requiring two-thirds Senate approval, but neither was it merely implementing current policy and law. It outlined the US role in defending Iraq from internal and external threats, in promoting reconciliation and combating terrorist groups.

For more than a year, the SFA was negotiated and finalized, but there was no meaningful consultation with Congress, no congressional debate on its merits and none sought by congressional leaders. In contrast to Congress’ passivity regarding policy toward “an unstable regime in an unstable region,” Iraq’s parliament voted on the SFA twice.

Noting that in foreign as well as domestic policy Obama is “acutely fond of executive orders designed to circumvent the legislative process,” Webb recalls that in 2009 the administration said it would return from the UN Copenhagen conference on climate change with a “binding” commitment for an emission-reduction program. So Webb wrote to remind the president that “only specific legislation agreed upon in the Congress, or a treaty ratified by the Senate, could actually create such a commitment.”

Webb notes that presidents now act as though they have become de facto prime ministers, unconstrained by the separation of powers. This transformation was dramatized in the Libya intervention:

“Was our country under attack, or under the threat of imminent attack? No. . . Were we invoking the inherent right of self-defense as outlined in the UN Charter? No. Were we called upon by treaty commitments to come to the aid of an ally? No. Were we responding in kind to an attack on our forces elsewhere, as we did in the 1986 raids in Libya after American soldiers had been killed in a Berlin disco? No. Were we rescuing Americans in distress, as we did in Grenada in 1983? No.”

Instead, “we took military action against a regime that we continued to recognize diplomatically, on behalf of disparate groups of opposing forces whose only real point of agreement was that they wished to rid Libya of [Moammar] Khadafy. This was not even a civil war” because there was “no cohesive opposition facing a regime.” The result? “Rampant lawlessness” perhaps related to the murder of the US ambassador and three other Americans, and “the regionwide dispersion of thousands of weapons from Khadafy’s armories.”

The question, Webb says, is whether in “a world filled with cruelty,” presidents should be allowed to “pick and choose when and where to use military force” by merely citing the “undefinable rubric of ‘humanitarian intervention.’”

Imperial presidents and invertebrate legislators of both parties have produced what Webb correctly calls “a breakdown of our constitutional process.” Syria may be the next such bipartisan episode.