With Tuesday's announcement that the FBI will join the expanding investigation, anyone who doubted the seriousness of the poisoning of the Flint, Michigan water supply should now recognize their error. After all, until the administration of Republican Governor Rick Snyder and his emergency manager in Flint knowingly jeopardized the health of thousands, the FBI feared Al Qaeda terrorists would do the same thing.

As the Detroit Free Press reported:

Gina Balaya, a spokeswoman for the U.S. Attorney's Office in Detroit, told the Free Press Monday that federal prosecutors are "working with a multi-agency investigation team on the Flint water contamination matter, including the FBI, the U.S. Postal Inspection Service, EPA's Office of Inspector General, and EPA's Criminal Investigation Division."
The office of U.S. Attorney Barbara McQuade said Jan. 5 that it was assisting the U.S. Environmental Protection Agency in a Flint drinking water investigation, but at that time, Balaya would not say whether the investigation was civil or criminal.

Back in 2002, there was no doubt that the FBI's investigations were very much criminal in nature. As Carl Cameron reported for Fox News on July 30 of that year:

Federal officials have arrested two Al Qaeda terror suspects in the U.S. with documents in their possession about how to poison the country's water supplies, Fox News has learned.
The first case involves James Ujaama, 36, who surrendered to the FBI last week in Denver. Sources say they found documents about water poisoning among several other terrorism-related documents in his Denver residence...Another former member of the mosque is also now in custody and suspected of plotting terrorist attacks. His name is Semi Osman and he too is accused of having documents about poisoning water supplies in his possession when he was arrested.

On February 11, 2003, FBI Director Robert Mueller testified to the Senate Select Committee on Intelligence about Al Qaeda terror threats within the United States that his agency was taking very seriously:

"Poisoning food and water supplies also may be an attractive tactic in the future. Although technologically challenging, a successful attempt might cause thousands of casualties, sow fear among the US population, and undermine public confidence in the food and water supply."

As it turns out, fears of terrorist attacks on American water supplies pre-dated the September 11 attacks. In October 2003, MSNBC examined the early warnings in a report titled, "U.S. water supply vulnerable":

In January of 2001 an urgent fax lit up the machines in the offices of water authorities in major cities around the country screaming about a letter the FBI intercepted from a terrorist group that indicated they "intend to disrupt water operations in 28 US cities." The fax said the FBI believed the threat was from a "credible, well known source, with an organizational structure capable of carrying out such a threat."
"Some people panicked...when they got that fax," says [Peter] Beering, who also wears the hat of Terrorism Preparedness Coordinator for Indianapolis. "It all depended on how much work they'd previously done with regard to security."

The letter was later determined to be a hoax. But to succeed, as the Indianapolis Water Company's Beering explained, terrorists "just have to make you believe the water is contaminated."

If the public suddenly lost confidence in the integrity of the water system, he said, there would be a domino effect. A panic run on bottled water and alternative water supplies.
A question he has asked to officials of various water authorities: "Are you prepared to empty a five, ten, fifteen million gallon...reservoir to prove to the public that it's safe to drink?"

U.S. law enforcement was wrestling with that dilemma long before Al Qaeda appeared on the scene. In 1972, authorities in Chicago arrested Allan Schwander and Stephen Pera over their plot to release a host of pathogens into the air and water supplies in the Windy City. In 1984, the Rajaneeshee cult in Oregon put salmonella in the food of several nearby restaurants and also considered (and rejected) "a much worse plan of attack: poisoning the local water supply and crashing a plane loaded with bombs into the county courthouse." Twelve years later, the New York Times recounted on March 6, 1998:

Members of an Illinois white-supremacist group planned to assassinate a lawyer who has battled hate groups, bomb the lawyer's Southern Poverty Law Center and public buildings, kill a judge, rob banks and poison water supplies, an F.B.I. agent testified today at a Federal court hearing.

After the May 2011 raid in Pakistan that killed Osama Bin Laden, U.S. intelligence revealed an Al Qaeda "playbook" amounting to a "strategic guide for how to attack the U.S." Infrastructure targets including water supplies were at the top of the list:

In the past, al Qaeda planned for attacks on water supplies have included an interest in mining dams and in poisoning water supply. Intelligence experts have also have found what appears to be information about safe houses around the world and about al Qaeda leadership.

In October 2013, Reuters announced, the FBI was once again "investigating possible threats to the water supply systems in Wichita, Kansas, and several other Midwestern cities that are as yet unsubstantiated, a spokeswoman said on Friday."
Ultimately, none of those terrorist attacks never came to pass. The nightmare of thousands of Americans killed and perhaps hundreds of thousands sickened by terrorist tampering with our water supplies has not yet materialized. To date, none of the usual domestic terror suspects--not Al Qaeda, not ISIS, not white supremacists, neither supposed militia members nor "lone wolves" of any stripe--has come to close.
Until now. In Flint. And the culprits putting American lives at risk weren't "radical Islamic terrorists" or "sovereign citizens," but Republican Governor Rick Snyder and his allies' radical ideology of de facto government sabotage.