At about 9:30 p.m. on March 19, 2003, the shooting phase of Operation Iraqi Freedom began, with an unsuccessful “decapitation strike” aimed at top Iraqi leadership, including Saddam Hussein. Shortly thereafter, President George W. Bush told the American people in a nationally televised address that we’d gone to war “to disarm Iraq, to free its people and to defend the world from grave danger.”

Ten years later, the future of “Iraqi Freedom” is unclear at best, but it’s evident that there wasn’t much to disarm and that the world was never in grave danger.

What has the Iraq War cost us, and what lessons, if any, have we learned?

Placing all the blame for the war on neoconservatives lets everyone else off far too lightly, it seems to me. The 2002-03 rush to war was abipartisan flight from responsibility.

In 2002, very few of our elected representatives were interested in doing basic due diligence before exercising the solemn responsibility that the Constitution gives Congress in the power “to declare War.” From late September 2002 on, copies of the 92-page National Intelligence Estimate on the Iraq threat were available to any member of the House or Senate who wanted to review it. Only a handful even bothered. Then-Sens. John Kerry, D‑Mass., and Hillary Clinton, D‑N.Y. — our current secretary of state and his predecessor — weren’t among the six senators who took the time to read the report before voting for war. Sen. Jay Rockefeller, D‑W.Va., explained that getting away to the secure room to read the NIE — a short walk away across the Capitol grounds — is “not easy to do” and that NIEs make for “extremely dense reading.”

The Beltway intelligentsia didn’t comport itself any better. In a recent article for the New Republic, “The Eve of Destruction,” TNR’s John B. Judis describes “what it was like to oppose the Iraq War in 2003.” Lonely: “within political Washington, it was difficult to find like-minded” opponents of the war. “Both of the major national dailies — The Washington Post and The New York Times (featuring Judith Miller’s reporting) — were beating the drums for war,” as were most of “Washington’s thinktank honchos.”

Not all of them, however. In a 2001 debate on Iraq with former CIA Director James Woolsey, my Cato Institute colleague, then-Chairman William Niskanen, argued that “an unnecessary war is an unjust war” and one we would come to regret having fought.

Niskanen was right. A new report from the Watson Institute for International Studies at Brown University tallies up the costs: nearly 4,500 U.S. troop fatalities, an eventual budgetary cost of some $3.9 trillion and more than 130,000 civilians as “collateral damage.”

Amateur ornithologist Sen. John McCain, R‑Ariz., calls the dovish Sen. Rand Paul, R‑Ky., a “wacko bird” for raising questions about unchecked presidential war-making. Still, Paul ruled the roost at last weekend’s Conservative Political Action Conference, winning CPAC’s presidential straw poll.

The Christian Science Monitor reports on another poll of CPAC attendees, in which “only 34 percent said the US should adopt a more muscular role [abroad]; 50 percent said the US should pull back, leaving it more to allies to take care of trouble spots.” George Will reported on ABC’s “This Week” on Sunday that what he saw at CPAC was “the rise of the libertarian strand of Republicanism, which has an effect in foreign policy that is a pullback from nation-building and other ambitions aboard that they never countenance from government at home.”

Bill Niskanen, who passed away last year at the age of 78, never tired of reminding conservatives that war is a government program — and an especially destructive one at that.

The message may be starting to sink in.