The Justice Against Sponsors of Terrorism Act (JASTA) cruised through both the House of Representatives and the Senate, with its final adoption coming just two days before the nation marked the 15th anniversary of the attacks that killed almost 3,000 people in New York, Washington and Pennsylvania on September 11, 2001.
US President Barack Obama on 23 September 2016 vetoed a bill that would have allowed the families of 9/11 victims to sue Saudi Arabia.
Fifteen of the 19 hijackers were Saudi nationals, leading to suspicions they were backed by Arab state's government.
And while lawmakers have threatened to call a vote as early as next week, Congressional rules could delay the override until after the November 8 election, when Obama could campaign against the bill - but from outside the White House.
The Justice Against Sponsors of Terrorism Act (JASTA) bill, passed by both the chambers of the Republican controlled Congress, would have jeopardized the long standing worldwide principles regarding sovereignty and would have made adverse impact with U.S. interests and nationals overseas, Obama said. But Saudi Foreign Minister Adel bin Ahmed Al-Jubeir denied in May that the kingdom made any threats over the bill.
Mrs Clinton's Republican opponent Donald Trump criticised the outgoing president for the veto, and also promised to sign the Bill if he enters the White House.
In a three-page statement, Obama listed his reasons for vetoing the bill, which he claimed would be "detrimental to US interests" if signed into law. Lawmakers from both parties have chosen the interests of the September 11 families seeking justice over those of the House of Saud.
Republicans will certainly use the veto to cast Obama as putting monarchs in Riyadh before United States terror victims. JASTA, he wrote, "would be detrimental to USA interests".
Though the concept of sovereign immunity generally shields governments from lawsuits, the bill creates an exception that allows foreign governments to be held responsible if they support a terrorist attack that kills US citizens on American soil. He argues terrorism-related issues are for policy officials to deal with, not the courts.
But Obama is "willing to take some heat", Earnest said, because the risks the bill poses to USA national security are too high.
"We also make a strong case that the most effective way for the United States to confront state sponsors of terrorism is to level a government-wide designation against them and take appropriate steps, including sanctions, to isolate them from the United States and the rest of the global community, that that is a forceful way to compel them to stop supporting terrorism", he said.
Some key lawmakers appear open to considering such arguments.
"I must veto the bill". Ben Cardin, D-Md., told NPR Thursday. Friday's veto was the twelfth of his presidency. "This is a disappointing decision that will be swiftly and soundly overturned by Congress", said JASTA co-sponsor Sen.
Sen. Chuck Schumer of NY, the Senate's No. 3 Democrat and a traditional Obama ally, came out swinging against Obama while predicting lawmakers would reverse it "swiftly and soundly". "I believe both parties will come together next week to make [the Justice Against Sponsors of Terrorism Act] the law of the land". Cornyn says he looks forward to the opportunity for Congress to override the veto. He has vetoed nine bills during his eight years in office, but has never been overridden.
Congress is determined to try to overturn the veto, which requires a two-thirds vote in the House and Senate. This is particularly true in the Senate, which is seen as the body more likely to uphold the veto. Such a vote won't happen before Tuesday, when that chamber meets for the full day.
It also puts the President at odds with family members of 9/11 victims, who protested outside the White House this week and spoke alongside lawmakers from NY and CT on Capitol Hill.
"If the Saudis did nothing wrong, they should not fear this legislation", Senator Schumer wrote. "We are outraged and dismayed at the President's veto of JASTA and the unconvincing and unsupportable reasons that he offers as explanation", they wrote.