The Kingdom of Saudi Arabia's massive implication in the death of 3,000 Americans on 9/11, I argued in February, is reason for the victims and their families to consider suing it for compensation. Three important developments have occurred since then,

The Kingdom of Saudi Arabia's massive implication in the death of 3,000 Americans on 9/11, I argued in February, is reason for the victims and their families to consider suing it for compensation. Three important developments have occurred since then, all of them propelling this idea forward.

• No loss of U.S. benefits: A U.S. law passed on last Sept. 22 seemed to limit the ability of 9/11 victims and their survivors to sue the Saudis or anyone else. To share in the open-ended federal compensation fund, states the "Air Transportation Safety and System Stabilization Act," they have to waive "the right to file a civil action (or to be a party to an action) in any Federal or State court for damages sustained as a result of the terrorist-related aircraft crashes of Sept. 11."

But Kenneth R. Feinberg, the special master in charge of dispensing the open-ended fund (which he estimates will total about $4 billion), informs me that another piece of legislation effectively reversed my interpretation of the law. On Nov. 19, Public Law 107-71 amended the above in the following manner: "The preceding sentence does not apply to a civil action to recover collateral source obligations, or to a civil action against any person who is a knowing participant in any conspiracy to hijack any aircraft or commit any terrorist act."

In effect, the law now distinguishes between 9/11's unknowing participants (such as the airlines or airports) and knowing ones (such as the terrorists themselves or those who sponsored or financed them). It keeps the former off-bounds but permits suing the latter.

In Feinberg's words, any person "in Saudi Arabia (or anywhere else) who provided assistance to the terrorists on September 11 can be sued by claimants participating in the Fund." Or, in his plain-English explanation, claimants can "have their cake and eat it too."

This amendment is wonderful news, permitting the families to accept an on-average $1.2 million from the U.S. taxpayers, then sue Saudi Arabia.

• More indications of official Saudi sponsorship of terrorism: Recent weeks have turned up some extraordinarily incriminating documents, such as a hard drive seized by U.S. troops in Sarajevo from a computer at the office of the Saudi High Commission for Relief of Bosnia and Herzegovina. An operative was arrested carrying documents that proved Saudi funding of the Hamas terrorist group to enable it to produce a short-range missile called the "Qassam."

U.S. intelligence sources have concluded that Saudi princes are spending millions of dollars to help large numbers of al Qaeda and Taliban members escape the American dragnet. One source told Middle East Newsline that "the money flow to al Qaeda continues from members of the royal family."

To staunch this flow of funds, U.S. authorities are taking the initiative, sometimes close to home. In March, they raided 16 locations, mostly in the Washington, D.C. area, primarily to learn more about two high-ranking residents of Saudi Arabia, Khalid bin Mahfouz and Cherif Sedky, and their role in funding al Qaeda.

• Progress against Libya: A Scottish appeals court in March upheld the conviction of a Libyan intelligence agent for the 1988 bombing of Pan Am flight 103, killing 270, a development that Allan Gerson, a lawyer for many Pan Am families, calls "a giant step" toward making sponsors of terrorism accountable.

The Scottish verdict closes 13 years of litigation and permits families of the victims finally to press civil claims against Libya's government, with full U.S. government endorsement: "The president expects Libya to fulfill [its] obligations," says the White House spokesman. "The court has spoken. It's time for Libya to act." Negotiations are indeed under way in Paris, with the families demanding more than $10 billion (or about $40 million per death).

Together, these three developments suggest that 9/11 claimants are on solid legal, factual and political grounds in seeking compensation from the kingdom. Should Riyadh reject their claims, they can demand per death as much as the Lockerbie families, which would bring their claim to more than $100 billion.

It's hard to think of a better way for ordinary Americans to help fight terrorism than for the 9/11 families to bring home to the Saudis the costs of sponsoring this hideous behavior.