WASHINGTON ― Congress offered a rare show of unity Wednesday when Republicans and Democrats in both chambers overwhelmingly voted to override President Barack Obama’s veto of a bill that allows the families of Sept. 11 victims to sue Saudi Arabia.

Legislators can now claim to have heroically stood up for all Americans against foreigners and “Washington elites” by voting for a bill opposed by virtually the entire executive branch.

Don’t believe them. Instead, consider the real impact of what Congress decided to do this week, and why its members behaved as they did.

The Justice Against Sponsors of Terrorism Act, known as JASTA, is rooted in a conspiracy theory. By supporting the legislation, lawmakers who know better are promoting the belief that there are still legitimate questions about whether the Kingdom of Saudi Arabia helped plan the horrific attacks of September 11, 2001. But there are no such questions ― at least, not if you trust the security apparatus that Congress continues to fund and rely on to keep America safe.

Multiple U.S. government investigations ― including the one that produced the much-discussed “28 pages” thought to describe Saudi sheikhs literally pelting bombs at the Twin Towers ― have cleared the Saudi government of involvement in 9/11.

“Saudi Arabia has long been considered the primary source of Al Qaeda funding, but we have found no evidence that the Saudi government as an institution or senior Saudi officials individually funded the organization,” the 9/11 Commission concluded.

You wouldn’t know it from reading the media coverage of the JASTA bill. Almost every article on the measure’s progress through Congress this year mentioned that 15 of the 19 hijackers responsible for thousands of deaths that day were Saudi citizens. Few of those stories went on to note that repeated inquiries have absolved the Kingdom of blame.

Sure, many Americans would have liked to see a different conclusion. That’s understandable. The Saudis are easy to hate, with their luxurious lifestyles, their myriad human rights abuses and their close association with some of the biggest disasters of U.S. foreign policy. But no matter how badly some people might like to see a connection between 9/11 and the Kingdom, the evidence simply is not there.

Eric Drapper-White House/Getty Images As the Iraq War took a turn for the worse, many critics alleged that it was a result of some sort of deal between then-President George W. Bush and the Saudis -- notably then-Ambassador Prince Bandar bin Sultan, seen here with Bush in 2002.

If lawmakers seriously believe that the questions about a Saudi role in the attacks ― questions spread by Donald Trump and others ― still have some merit, they could organize yet another U.S. government inquiry. After all, if Washington managed to get some $20 million worth of pointless political showmanship out of the tragedy in Benghazi, Libya, just imagine how much lawmakers might be willing to spend to investigate 9/11 one more time.

But the bill’s supporters are playing coy. They won’t admit that they’re essentially dismissing years’ worth of analysis after previously endorsing it.

All Congress wants to do, according to bill proponent Sen. Chuck Schumer (D-N.Y.), is get 9/11 families a day in court where they can air their concerns ― and where Saudi Arabia can be proven innocent if it is indeed blameless.

That scenario, of course, takes as its premise the idea that 9/11 families have previously been ill-served.

That’s easy to believe that if you share 9/11 truthers’ view that the U.S. government is a compromised institution hiding things from Americans to serve shady powerful interests, whether it’s Jews, Muslims or any other group you dislike.

Is that what the bill’s supporters on the Hill think? Probably not. Lawmakers seem driven by sheer cynicism, not sincere naivete.

If you’re a politician concerned with winning elections, the JASTA bill is the kind of cheap stunt that never gets old. Voting for JASTA ties you to an unqualified good (9/11 victims and their families) while positioning you as a warrior against what’s broadly seen as an unqualified bad (a Muslim-led monarchy best known abroad for not allowing women to drive). You probably won’t lose points with voters by supporting it, but you’ll definitely be seen as repulsive if you oppose it.

You might even see it as an opportunity to settle scores. Some Republicans voted for the bill just so they could get the chance to override an Obama veto before the end of his presidency, one GOP lawmaker told The Huffington Post on the condition of anonymity.

If you have a creeping feeling that it’s maybe, possibly, not the best idea to pass legislation in response to conspiracy theories, Schumer and his colleagues would probably shrug and ask: What’s the harm? Victims’ families will be happy, and the Saudis will remain free to prove their innocence. Even if the bill’s attack on sovereign immunity has dangerous consequences for U.S. personnel abroad ― which, yep, it does, as the president has warned ― you can try a fix a little later, as 28 pro-JASTA senators have already suggested they will do.

Tom Williams via Getty Images Sen. Dianne Feinstein (D-Calif.) is one of the lawmakers who voted for JASTA despite previously attacking conspiracy theories linking the Saudis to 9/11. She and 27 others signed a letter asking for improvements to the bill after they voted for it.

But there are consequences to this kind of pandering.

Until Congress does find a way to signal that the U.S. retains some respect for international law, there remains the potential harm to Americans that Obama, the secretaries of state and defense, the head of the CIA and others have warned about if other countries follow suit and begin to pursue cases against the U.S.

And there’s a deeper, perhaps irreversible damage to the political environment and conversation in this country.

The real winners here are the conspiracy theorists ― the people who argue that the U.S.’s closest Muslim-majority ally stabbed it in the back, the people who worry about having attacked the “wrong enemy” following 9/11 and feel a strong urge to correct that error, and the foreign leaders keen to downplay their own offenses and exploit the sense that America and its allies (like the Saudis) are to blame for the world’s ills. Consider the recent New York Times op-ed by Iranian foreign minister Javad Zarif, who manages to blame all the problems in the Middle East on the Saudis’ brand of religion while avoiding any mention of Iran’s support for the vicious Assad regime in Syria, Hezbollah in Lebanon or al Qaeda’s international operations.

Who loses? People who want to have fact-based conversations about reducing support for terror in the Muslim-majority world. Part of the way to actually do this would be to hold Saudi Arabia accountable for its repression, its state-sponsored fundamentalism and its citizens’ links to terror financing. But when the Saudis see American lawmakers glorifying disproven allegations, the president saying their region is essentially hopeless and international media chasing gratuitous stories about Saudi moral hypocrisy, they’re less likely to accept criticism based on real concerns. That doesn’t help anyone ― and it virtually guarantees more distrust and tension in the Middle East.

Oh, and don’t forget those 9/11 families about whom Congress appears so concerned. With Wednesday’s vote, the families who want to sue Saudi Arabia will feel they’ve won a major symbolic victory. Lawmakers can posture and pretend that’s what they’ve offered. In reality, they’ve encouraged a line of thinking that will never deliver real closure. They’ve also drawn out a legal process that will inevitably leave the families disappointed, because it will likely end up relying on the same U.S. government investigations that have found the Kingdom innocent multiple times already.

But hey, at least Congress got to feel like it did something.

Ryan Grim contributed reporting.

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