In the wake of Thursday's suicide plane crash into the Austin office of the Internal Revenue Service, the debate is raging over the meaning of Joseph Stack's attack. While Glenn Greenwald and Matthew Yglesias ponder whether the incident constitutes an act of terrorism, bloggers on the left and right each try to assign Stack's political paternity to the other.

What is beyond dispute, as the Christian Science Monitor documented, is that Thursday's destruction in Austin is just "one incident in a string of violent threats and assaults directed toward the agency in recent years." And predictably, as ABC reported Friday, right-wing extremist organizations, white supremacists and militia groups were quick to hail Joe Stack as a "hero."

Meanwhile, conservative stalwarts like Human Events editor Jed Babbin and Senator Scott Brown seemingly rationalized the carnage in Austin by announcing "people are frustrated" and "no one likes paying taxes." But as it turns out, violence targeting the IRS and incendiary rhetoric justifying the intimidation of the agency and its personnel are hardly recent developments:

The Treasury Inspector General for Tax Administration (TIGTA), which oversees the IRS, handles an average of 918 threats made against IRS employees every year, according to the agency. Between 2001 and 2008, court cases resulting from those threats have resulted in 195 convictions, according to TIGTA.

“This is not something new,” says J. Russell George, director of TIGTA. “The use of the airplane was unanticipated, but this is not something new, not at all.”

And, in some extreme right-wing circles, a very welcome turn. As ABC detailed:

[F]or an alarmingly growing number of Americans Stack is a hero. The Web was studded with praise for Stack almost immediately after his plane slammed into the Austin office complex Thursday morning. The admiring salutes appearing on sites ranging from Facebook to the pages of extremist groups reflect what experts say is an "explosive growth" in the anti-government patriot movement…

Bob Schulz, founder of the anti-government We the People Foundation, said that while he only advocates non-violent means of protest, he can understand Stack's motives and said it is a reflection of a movement unlike any he's ever seen.

"There's a huge patriot movement," Schulz said. "I've been doing this kind of work for 30 years. Never have I seen the likes of what's going on now. It's delightful."

But what is delightful to Bob Schulz or the members of Stormfront is frightening to most Americans.

To be sure, the language directed at the IRS was threatening.

"Gestapo-like tactics."

"The IRS is out of control!"

"Which would you prefer: having your wallet or purse stolen or being audited by the IRS?"

"You don't need to send in armed personnel in flak jackets."

"Well Mr. Big Brother IRS Man, let's try something different, take my pound of flesh and sleep well."

But even more disturbing is that only the last of those five statements came from Thursday's alleged Austin pilot, Joseph Stack. The rest came from some of the leading voices of the Republican Party during its late 1990's crusade against the IRS.

As David Cay Johnston describes in his book Perfectly Legal, the GOP during the Clinton administration waged an all-out war on the IRS, turning the priorities for auditing Americans upside-down. As Delaware Republican Senator William Roth's Finance Committee held hearings in 1997 and 1998, Mississippi's Trent Lott decried the IRS' "Gestapo-like tactics." Frank Murkowski (R-AK) similarly denounced those supposed "Gestapo-like tactics" while excoriating the Agency, "You don't need to send in armed personnel in flak jackets." Don Nickles of Oklahoma raged, "The IRS is out of control!" Meanwhile, GOP pollster and wordmeister Frank Luntz quizzed focus groups with his favorite question, "Which would you prefer: having your wallet or purse stolen or being audited by the IRS?"

Even as IRS Director Charles Rossotti warned Congress about an epidemic of tax cheating which had reached $195 billion a year, Senator Phil Gramm in May 1998 denounced the agency. Peddling myths of jack-booted IRS agents tormenting American taxpayers, Gramm called on Rossotti to fire his 50 worst employees. Gramm concluded:

"I have no confidence in the Internal Revenue Service of this country. You do not have a good system. This agency has too much unchecked power."

No surprise, Congress went on to pass and President Bill Clinton to sign the IRS Reform and Restructuring Act in 1998. And as Johnston documented, "In 1999, for the first time, the poor were more likely than the rich to have their tax returns audited."

Sadly, the picture of an unaccountable praetorian guard at the IRS painted by Republicans simply wasn't true.

In 2000, as David Cay Johnston again reported in the New York Times:

Two years ago, Congress, warned in hearings that the Internal Revenue Service was bullying many innocent Americans, passed a law requiring that the agency fire workers who harassed taxpayers.

But not one of the first 830 complaints of taxpayer harassment filed under the new law has been upheld by the I.R.S. or its new Congressionally designated watchdog, according to new data.

Investigations by the I.R.S. and the watchdog, the Treasury Inspector General for Tax Administration, found evidence that some of the complaints were bogus -- made in an effort to derail audits and tax collections. Others were either without merit or involved misconduct that fell far short of the Congressional definition of harassment.

Former FBI director and Judge William Webster, who headed up an investigation ordered by Roth's Senate Committee, concluded "No evidence was found of systematic abuses by agents." When a GAO inquiry similarly revealed "no corroborating evidence that the criminal investigations described at the hearing were retaliatory against the specific taxpayer," Senator Roth tried to prevent its report from becoming public.

But the damage was already done. Not only was the IRS's ability to pursue tax fraud gutted, but the incendiary rhetoric about the agency Republicans introduced was quickly propagated among tax protestors nationwide. And as the Bush Justice Department documented, that included anti-tax terrorists:

On April 4, 2003, the FBI arrested David Roland Hinkson, a constitutionalist and tax protestor, for attempting to arrange the murders of a federal judge, an Assistant U.S. Attorney, and an IRS Agent whom he blamed for his legal problems regarding a tax evasion case against him. Between December 2002 and March 2003, Hinkson offered two individuals $10,000 for committing all three murders. On January 27, 2005, Hinkson was found guilty on three counts of solicitation to commit murder after a three week jury trial in Boise, Idaho. On June 3, 2005, Hinkson was sentenced to 43 years in federal prison.

As it turned out, Hinkson owed over a million dollars in taxes on his dietary supplement business, Water Oz. Echoing the sentiment Stack expressed online today, Hinkson described the IRS raid he endured in 2002:

"I believe that...[government officials] orchestrated the raid on Water Oz and my home for the sole purpose of murdering me and ending the lawsuit that was filed against them by me."

As the Monitor noted, these kinds of episodes have been underway for years, even before the most recent expansion of enforcement efforts by the IRS beginning in 2008:

Last March, a Florida man was sentenced to 30 years in prison after hiring a hit man to kill an IRS worker who was auditing his tax return, and to burn down IRS offices in Lakeland, Fla. The hit man turned out to be an undercover FBI agent who helped arrest Randy Nowak.

In 2008, Earnest Milton Barnett was sentenced to 20 years in prison after ramming his Jeep Cherokee into the IRS’s Birmingham, Ala., offices.

In 1997, two men set fire to IRS offices in Colorado Springs, destroying the building and taxpayer files. In 2003, the men – Jack Dowell of Pensacola, Fla., and James Floyd Cleaver of Colorado Springs – were sentenced to at least 30 years in federal prison and ordered to pay $2.2 million in fines.

Following Joseph Stack's deadly assault in Texas, Mark Potok, director of the Intelligence Project for the Southern Poverty Law Center, "We've had a right wing tax protest movement going back several decades now," adding, "They were very hot in the 1990s, but they are very much still out there." And regardless of Stack's potential motivations, politics or psychoses, that right-wing threat remains very real. As Treasury Inspector General George put it, "We’ll have to try to stay one step of ahead of these people in the future."