Saudi Arabia probably takes the prize, although the US has done its share of sponsoring terrorists as well. From the Veteran Intelligence Professionals for Sanity at antiwar.com:
MEMORANDUM FOR: The President
FROM: Veteran Intelligence Professionals for Sanity
SUBJECT: Is Iran the “World’s Leading Sponsor of Terrorism?”
We are concerned by recent strident and stark public statements from key members of your Administration that paint Iran in very alarmist terms. The average American, without the benefit of history, could easily be persuaded that Iran poses an imminent threat and that there is no alternative for us but military conflict.
We find this uncomfortably familiar territory. Ten years ago former President George W. Bush was contemplating a war with Iran when, in November of 2007, intelligence analysts issued a formal National Intelligence Estimate (NIE) debunking the prevailing conventional wisdom; namely, that Iran was on the verge of getting a nuclear weapon. The NIE concluded that Iran had stopped working on a nuclear weapon in 2003.
Recalling this moment in his memoir, Decision Points, President Bush noted that the NIE’s “eye-popping” intelligence findings stayed his hand. He added this rhetorical question: “How could I possibly explain using the military to destroy the nuclear facilities of a country the intelligence community said had no active nuclear weapons program?”
We believe that you are facing a similar situation today. But instead of an inaccurate claim that Iran has nuclear weapons, the new canard to justify war with Iran is the claim that Iran remains the “world’s leading state sponsor of terrorism.” This is incorrect, as we explain below.
One of the recurring big bipartisan lies being pushed on the public with the enthusiastic help of a largely pliant media is that Iran is the prime sponsor of terrorism in the world today.
In the recent presentation of your administration’s National Security Strategy for 2018, the point is made that:
“Iran, the world’s leading state sponsor of terrorism, has taken advantage of instability to expand its influence through partners and proxies, weapon proliferation, and funding. . . . Iran continues to perpetuate the cycle of violence in the region, causing grievous harm to civilian populations.”
Those sentiments are echoed by several other countries of the Middle East. Saudi Arabia’s Foreign Minister, Adel al-Jubeir, for example, declared in October 2015 that: Iran “is the biggest sponsor of terrorism in the world, and it is working on destabilizing the region.”
The Saudi foreign minister conveniently declined to mention that 15 of the 19 terrorists who hijacked planes and attacked America on 11 September 2001 were Saudis, not Iranians. And, while Iran was an active promoter of terrorism two decades ago, it is no longer in the forefront of global terrorism. Ironically, that dubious distinction now goes to Iran’s accusers – first and foremost, Saudi Arabia.
To continue reading: Intel Vets Tell Trump Iran Is Not Top Terror Sponsor