Group which campaigned for the law called result 'justice' for the dead and bereaved

15 of the 19 9/11 hijackers were Saudi, a fact which has fueled claims of official complicity in the atrocity

fears foreign government bringing in similar legislation and trying to bring politically-motivated cases against U.S.

President Barack Obama has said congress failed to 'do the right thing' by giving victims of 9/11 and their families the go-ahead to sue Saudi Arabia by vetoing a bill he had introduced.

President Obama spoke about the congressional decision during a CNN town hall on Wednesday night, saying it is an example of when politicians 'have to do something hard'.

'Frankly, I wish Congress here had done what's hard,' Obama said.

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President Barack Obama has said congress failed to 'do the right thing' by giving victims of 9/11 and their families the go-ahead to sue Saudi Arabia by vetoing a bill he had introduced

'If you're perceived as voting against 9/11 families right before an election, not surprisingly, that's a hard vote for people to take.

'But it would have been the right thing to do ... And it was, you know, basically a political vote.'

The veto was the first time Obama has been overridden during his time in office, CNN reports.

And while he said he understands people carry 'the scars of 9/11', but said he doubts the legislation will be good for the U.S. in the future.

'Frankly, I wish Congress here had done what's hard,' Obama said of Congress vetoing his bill

'But it would have been the right thing to do ... And it was, you know, basically a political vote,' Obama said on Wednesday

'What this legislation did is it said if a private citizen believes that having been victimized by terrorism - that another country didn't do enough to stop one of its citizens, for example, in engaging in terrorism - that they can file a personal lawsuit, a private lawsuit in court,' Obama said during the town hall.

'And the problem with that is that if we eliminate this notion of sovereign immunity, then our men and women in uniform around the world could potentially start seeing ourselves subject to reciprocal laws.

'The concern that I've had has nothing to do with Saudi Arabia per se or my sympathy for 9/11 families.

Policy blow: Obama has never had his veto over-ridden by Congress, as happened on Wednesday. He had just been presented with a NASCAR helmet in the White House when the Senate voted

Historic moment: The Senate's first ever vote to overturn an Obama veto was by 97-1

Leaders: Chuck Schumer, the Democratic New York senator and John Cornyn, Republican from Texas, led the effort to vote to overturn the veto

'It has to do with me not wanting a situation in which we're suddenly exposed to liabilities for all the work that we're doing all around the world.'

The comments came after a dramatic day saw the Senate voted first to overturn President Barack Obama's veto of the Justice Against Sponsors of Terrorism Act.

It voted 97 to one against the veto - a situation called 'embarrassing' by the White House, which is furious at the legislation.

Hours later, the House of Representatives voted by a resounding 348-76 to do the same, meaning the Act becomes law.

The Saudi connection: Fifteen of the 19 who committed the worst ever terror attack on the U.S. were Saudi - a fact which has fueled claims of its government having a role in the attacks. The Saudi nationals were: Top row - left to right: Abdulaziz al-Omari; Wail al-Shehri; Waleed al-Shehri; Satal al-Suqami ; Mohand al-Shehri. Middle - left to right: Hamza al-Ghamdi; Ahmed al-Ghamdi; Hani Hanjour; Khalid al-Mihdhar; Majed Moqed. Bottom, left to right: Nawaf al-Hamzi; Salem al-Hamz; ,Ahmed al-Haznawi; Ahmed al-Nami; Saeed al Ghamdi.

Leader of evil ring: Mohamed Atta was the overall leader of the 9/11 attacks

'Overriding a presidential veto is something we don't take lightly, but it was important in this case that the families of the victims of 9/11 be allowed to pursue justice, even if that pursuit causes some diplomatic discomforts,' said Sen. Chuck Schumer, the Democratic senior senator from New York.

'It means we'll be able to hold accountable the people who helped murder 3,000 people. At the personal level, this means justice,' Terry Strada, a 9/11 widow who leads the group which as lobbied for the law, told the New York Daily News.

White House spokesman Josh Earnest claimed members of the Senate Judiciary Committee were unfamiliar with the bill's impact on military personnel and voted to uphold it anyway.

The comments reflect White House frustration after failing to persuade Senate Democrats to stand by the president. If the House follows suit, the override will be Obama's first.

Foreign ally: The measure against Saudi is opposed by Obama who sees the country, led by King Salman (center) as a crucial part of U.S strategy

Defense Secretary Ash Carter, in a letter Monday to a senior member of Congress, had said he was sympathetic to the intent of the measure.

But the legislation could lead to the public disclosure of American secrets and even undercut counterterrorism efforts by sowing mistrust among U.S. partners and allies, according to Carter.

But one of the bill's leading proponents, Sen. John Cornyn, a Republican from Texas, dismissed Obama's concerns as 'unpersuasive.' Cornyn, the Senate's second most senior Republican, and other supporters said the bill is narrowly tailored and applies only to acts of terrorism that occur on U.S. soil.

Horror: 15 years on from the 9/11 attacks, the victims who survived and the families of the lost, are still fighting to sue Saudi Arabia. This was the scene shortly after the second plane hit the two towers of the World Trade Center

SAUDI: OIL-RICH ALLY Saudi Arabia is the richest and geographically largest Middle Eastern country - and a key U.S. ally. Currently its biggest military role for the U.S. is in the fight against ISIS. It allows overflight of US aircraft from other bases in the Gulf. Withdrawing that co-operation would make air operations against ISIS extremely difficult. Saudi also contributed fighter planes to the effort, basing them in Turkey. The Kingdom of Saudi Arabia holds $116 billion in Treasury debt, Bloomberg revealed earlier this year - a tiny fraction of the $1 trillion owned by China. Selling the holdings, something which has been suggested as a response to the Act, would be unlikely to damage the U.S. economy. But private Saudi money is widely invested in the U.S. Prince Alwaleed bin Talal, a member of the ruling al-Saud family and a billionaire investor has stakes in a huge range of big names just by himself, including Citigroup, 21st Century Fox, and the Plaza Hotel in New York. He is the tip of an iceberg, with billions of privately-invested Saudi cash on Wall Street and beyond. Advertisement

'This bill is about respecting the voices and rights of American victims,' Cornyn said.

Families of the victims and their attorneys disputed concerns over the legislation as fearmongering aimed at derailing the legislation that they have long urged Congress to pass.

Ben Cardin, a senator from Maryland who was one of the Democrats who broke with Obama and voted to override, said 'the risks of shielding the perpetrators of terrorism from justice are greater than the risks this legislation may pose to America's presence around the world.'

The legislation gives victims' families the right to sue in U.S. court for any role that elements of the Saudi government may have played in the 2001 attacks.

Fifteen of the 19 Sept. 11 hijackers were Saudi nationals. There have been persistent claims of elements Saudi Arabian involvement - although they have never been tested in court.

The 9/11 commission report's findings on Saudi - which were redacted until earlier this year - disclosed that the first major Al Qaeda figure picked up after the attacks, terror mastermind Abu Zubaydah, had a private number for a company which managed the estate of Saudi's then ambassador to Washington, Prince Bandar.

He also had for an unlisted number for a bodyguard at the Saudi Embassy in Washington in his phonebook, which was seize during the raid in Pakistan in which he was held.

Link: Prince Bandar was the Saudi ambassador to Washington and a royal figure known to have a very close relationship with George W. Bush. A private number for the company which ran his Colorado estate was found in an al Qaeda mastermind's phone directory in early 2002

Aftermath: A total of 2,996 people died on 9/11, 2,606 of them on the ground at the World Trade Center and in its environs. Saudi liabilities in a successful court case would run into the billions - and the activities of Abu Zubaydah (right) could be critical in the actions.

Courts would be permitted to waive a claim of foreign sovereign immunity when an act of terrorism occurs inside U.S. borders, according to the terms of the bill. Saudi Arabia has objected vehemently to the legislation.

Obama vetoed the measure last week, telling lawmakers the bill would make the U.S. vulnerable to retaliatory litigation in foreign courts that could put U.S. troops in legal jeopardy.

The bill's proponents have disputed Obama's rationale as 'unconvincing and unsupportable,' saying the measure is narrowly tailored and applies only to acts of terrorism that occur on U.S. soil.

Carter amplified Obama's concerns in a Sept. 26 letter to Rep. Mac Thornberry of Texas, the Republican chairman of the House Armed Services Committee and an opponent of the legislation. Thornberry last week urged his GOP colleagues to let Obama's veto stand.

SAUDI'S REVENGE WARNING Saudi Arabia and its allies are warning that U.S. legislation allowing the kingdom to be sued for the 9/11 attacks will have negative repercussions. The kingdom maintains an arsenal of tools to retaliate with, including curtailing official contacts, pulling billions of dollars from the U.S. economy, and persuading its close allies in the Gulf Cooperation Council to scale back counter-terrorism cooperation, investments and U.S. access to important regional air bases. 'This should be clear to America and to the rest of the world: When one GCC state is targeted unfairly, the others stand around it,' said Abdulkhaleq Abdullah, an Emirati Gulf specialist and professor of political science at United Arab Emirates University. Saudi foreign minister Adel al-Jubeir told reporters in June that the U.S. has the most to lose if JASTA is enacted. Despite reports that Riyadh threatened to pull billions of dollars from the U.S. economy if the bill becomes law, al-Jubeir says Saudi Arabia has only warned that investor confidence in the U.S. could decline. Advertisement

In the letter, Carter described the potential for litigants to seek classified intelligence data and analysis and sensitive operational information to establish their cases in what could be an 'intrusive discovery process.'

If the U.S. were sued overseas, a foreign court would decide whether the information should be protected from disclosure, he said. Paradoxically, the information could be central to a defense against the accusations.

'Disclosure could put the United States in the difficult position of choosing between disclosing classified or otherwise sensitive information or suffering adverse rulings and potentially large damage awards for our refusal to do so,' Carter wrote.

Kristen Breitweiser, a 9/11 widow and co-chair of September 11th Advocates, criticized Carter's assessment, saying that the defense secretary had testified before Congress last week that he wasn't an expert on the bill.

Speaking at a forum in Washington, CIA Director John Brennan said he was concerned about how Saudi Arabia, a key U.S. ally in the Middle East, would interpret the bill. He said the Saudis provide significant amounts of information to the U.S. to help foil extremist plots.

'It would an absolute shame if this legislation, in any way, influenced the Saudi willingness to continue to be among our best counter-terrorism partners,' Brennan said.

Obama has issued 12 vetoes during his presidency. None have been overridden until now, a rare feat given Republicans' longstanding control of Congress.

His Republican predecessor George W Bush also issued 12 vetoes, of which four were overridden. The last president to avoid an override was the legendary Democratic congressional dealmaker - and former senator and congressman - Lyndon Johnson.

The two senators not to vote at all were Tim Kaine, the Democratic vice-presidential nominee, and Bernie Sanders, the independent who lost the Democratic presidential nomination race and who was campaigning for Hillary Clinton when the vote took place.

Neither of the presidential candidates has commented on the vote.