Heading into the weekend that will mark the 15th anniversary of 9/11, the House of Representatives has unanimously passed the Justice Against Sponsors of Terrorism Act (JASTA). The bill passed by unanimous voice vote, as it did in the Senate back in May.

The bill allows families of victims of the 9/11 attack to sue Saudi Arabia in US courts over the attack, based on evidence that the Saudi government played a role in supporting al-Qaeda in the lead-up to the attack. President Obama repeatedly vowed to the veto the bill if it got through Congress, claiming “taxpayers” are at risk.

The risk is that, as far back as April, Saudi Foreign Minister Adel al-Jubeir was threatening to deliberately collapse the US treasury market in retaliation for the bill by selling some $750 billion in Saudi-held assets on the market. Jubeir’s initial threat was followed almost immediately by a chorus of officials coming out against the bill.

Unanimous yes votes in both houses of Congress, however, put President Obama in a tricky situation, as he faces what could easily be the first successful veto override of his presidency. Though it is believed some Democrats won’t challenge the president, and will thus switch sides on the veto override vote, there are strong indications that there may still be enough left to override the veto.

While there was already substantial support for the bill in Congress, there was also momentum gained in July with the release of the classified “28 pages” of the 9/11 Report, which centered on Saudi government involvement in the attack. The report detailed substantial financial support from the Saudi royal family to people who facilitated the attack.

It remains to be seen if the Saudi government follows through with threats to the US Treasury market. The market has already been absorbing steady sales out of eastern Asia, particularly from China, and would likely be unable to absorb another $750 billion debt dump.