On September 12, 2001, Americans learned that 15 of the 19 commercial-airplane hijackers of the previous day were Saudis.

The thought that went through many minds was, What are the Saudis thinking?

Were these 15 individual suicidal decisions, or does 9/11 represent a break in our mutually-beneficial relationship stretching back to World War II?

From that date until today, those questions have largely gone unanswered. Unanswered because the government of the United States has engaged in a sustained and effective campaign to keep the American public from knowing the truth.

And we may ask: Why?

These are some of the questions that have preoccupied me since co-chairing the congressional inquiry into 9/11. They arose from the truth that surfaced, which included: The first two hijackers who entered the United States did so through Los Angeles International Airport in mid-January 2000. Within days they were urged by a shadowy man, already described in an FBI report as an “agent” of the Saudi government, to relocate to San Diego with promises of extensive support—promises on which he promptly delivered.

The agent’s cover was as a ghost employee of a contractor to an agency of the Saudi government—paid a salary and allowances but never expected to show up and work. His real job was to monitor Saudi youth in San Diego getting an education to ensure they were not also plotting the overthrow of the monarchy.

When the two future hijackers reached San Diego, the agent’s allowances were substantially increased. Upon their arrival the agent secured and paid for an apartment. He arranged flight lessons. He introduced them to a tight circle of Muslims, primarily Saudis, who offered additional support.

Yet the support being funneled to the two visitors proved insufficient for their decidedly non-Islamic tastes—alcohol, strip clubs, even a desired, though unfulfilled, marriage to a stripper.

The agent then tapped another source of funds: a welfare account maintained for the benefit of Saudis in need by the wife of the kingdom’s ambassador to the United States.

That is some of what we do know, and we got a sufficient glimpse to know what we didn’t know. Still unanswered after nearly 10 years are the questions of the full extent of the Saudi pre-9/11 involvement: Did any or all of the other 17 receive support from Saudi interests? Why would Saudi Arabia do this? Do the Saudis have the will and capability to aid future attacks against the United States?

And most important: Why the cover-up by our government?

I have attempted to address these questions in the final report of the congressional commission and the nonfiction book Intelligence Matters, published in 2004. Each was censored by authorities in the intelligence community, particularly on the role of the Saudis in 9/11. I am now attempting to provide these answers in the form of fact wrapped in fiction in my novel "Keys to the Kingdom."

Some have claimed my statements and anxieties are over the top, that there are less incendiary explanations for what the Saudi and U.S. governments have done. But a string of recent occurrences has brought to the surface the suspicion of direct, deep Saudi involvement in 9/11.

Why would the Saudis have given substantial assistance to at least two of the hijackers, and possibly all 19? The answer I have come to is survival—survival of the state and survival of the House of Saud.

The Saudi regime in the late 1990s faced the prospect of a repeat of the 1979 Iranian revolution, when young revolutionaries toppled the shah. Osama bin Laden was ascending. He had achieved hero status—in his country of birth, Saudi Arabia, and across much of the Muslim world—for his work with the mujahedin in expelling the Soviets from Afghanistan.

He had successfully bombed two U.S. embassies in Africa. He had trained thousands of potential terrorists in his Afghan camps. And he was planning even greater attacks—this time within the United States itself.

But bin Laden recognized a deficiency: Most of those who would be spirited into the United States had never been there before and did not speak English. How could they survive and maintain anonymity while they completed the final planning, practiced and executed an enormously sophisticated attack? The Saudis, who were known to have a global network of agents to monitor their youth against the prospects of another Iran, could provide the support infrastructure to make this possible. The threat of civil unrest against the monarchy, led by al Qaeda, could be the leverage for access to this network.

The Arab Spring has posed a similar threat to the survival of the state and the House of Saud.

There have been at least three responses from the palace.

Beheadings, the traditional means of traumatizing the population into submission, have surged. According to Amnesty International, at least 27 such executions occurred during the first five months of 2011. This was the same number as the total for 2010. Another 100 or more wait on death row.

Religious organizations, many aligned with the austere Wahhabi sect and the religious police, have been allocated an additional $200 million.

The royal treasury, swollen by $214 billion in oil revenues last year, has been opened to essentially buy off the people. Public employees have received an additional two months’ salary; $70 billion has been lavished on 500,000 units of low-income housing.

One of the few reformists in the royal palace, Prince Talal bin Abdul Aziz, brother of King Abdullah, has said, “These people want to preserve their power, their money, and their prestige, so they want to keep the status quo. They are afraid of the word ‘change.’ This is a problem because they are shortsighted, but the difficulty is I don’t know how to change their way of thinking.”

An insight into how far the regime might go in defending and perpetuating the status quo occurred in May of this year at the Vienna meeting of the World Health Organization.

Advancing its policy of avoiding the proliferation of weapons of mass destruction, nuclear or biological, the United States offered a resolution that would have required all 193 members of the WHO to either declare they were smallpox-free or—as would be the case with the United States—to commit to the destruction of any smallpox pathogens held in laboratories or elsewhere within five years.

Throughout history, smallpox has been a scourge of mankind, and the virus remains the only communicable human disease successfully erased from nature, a miracle of organization and determination. There is only one way it can reappear, and that is in a weaponized form from a nation or group bent on mass catastrophe and worldwide havoc. The results of any dissemination would automatically be classified as a crime against humanity. This resolution to destroy all samples was successfully filibustered by Iran.

It is not surprising that a country that for more than a decade has sought to develop a nuclear capability would also be seeking a biological weapon. What was surprising was Saudi Arabia, one of Iran’s staunchest opponents, declaring that it “strongly disagreed” with the United States' position.

Why would the kingdom abandon its most important ally to support a nation that for the past 30-plus years has been considered its archenemy? Could it be that Saudi Arabia is also developing biological weapons?

The most perplexing unanswered question remains: Why would the United States engage in a cover-up? Many have pointed to the special personal friendship between the royal family and the highest levels of our national government. The fact that the Saudis were allowed to fly a planeload of their elite home from the United States in the days immediately after 9/11, when all other commercial aviation was grounded, is often cited as support for that position. In fact, all that actions such as this do is make America’s post-9/11 reaction to the Saudis even more mysterious.

Secrets deemed this critical by both governments are bound to be buried under many layers of official protection and unofficial obfuscation. The actions since 9/11 are a perverted application of Winston Churchill’s truism on the Allies’ plans to end World War II: “In wartime, truth is so precious that she should always be attended by a bodyguard of lies.”

If one method of disclosing precious truth doesn’t work, you try another. I’d always wanted to try my hand at a novel—to place characters of my own invention in challenging and intriguing situations that tested and defined their wits, strength, courage, and moral fiber. Now I had both motivation and material. Having been thwarted in my “real life” efforts to bring out the answers to these questions, which should be among the highest priorities to our citizens, I resorted to fiction, to the imaginative world of “What if?” With the publication of "Keys to the Kingdom," I feel I have finally conveyed the reality I’ve pursued for so long.

This post originally appeared at The Daily Beast.