The Bundy Ranch controversy has now divided Nevada's two United States Senators. While Majority Leader Harry Reid (D-NV) referred to Bundy's armed supporters as "domestic terrorists," his Republican colleague Dean Heller praised them as "patriots."
Their disagreement begs the question: What do you call someone who owes the United States government a million dollars and threatens violence against federal officials seeking to collect it? Whatever you may believe, for the Bush administration there was no doubt about the answer. The likes of Cliven Bundy and his gun-toting militia allies would indeed be considered domestic terrorists.
That's the inescapable conclusion from the FBI's report, "Terrorism 2002-2005." The document didn't merely define "domestic terrorism" as "the unlawful use, or threatened use, of force or violence by a group or individual based and operating entirely within the United States or Puerto Rico without foreign direction committed against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof in furtherance of political or social objectives." The Bureau also provided some helpful histories of domestic terrorism the FBI successfully prevented.
For example, consider the 2003 arrest of David Hinkson, a tax evader who owed the IRS over a million dollars. As the FBI's terrorism report summed it up:

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 the ADL reported in 2005, Hinkson then like Bundy now refused to acknowledge the legitimacy of the federal claims against him, claims up upheld by U.S. District Judge Edward Lodge:

The tax case against Hinkson stemmed from his failure to pay almost a million dollars in income taxes between 1997 and 2000 and for refusing to file tax returns or to withhold income tax from the salaries of employees working for his multi-million dollar business, Water Oz, which sold dietary supplements. Hinkson often paid his employees in silver dollars (some anti-government extremists considered paper money illegal and unconstitutional).
An IRS investigation, which began in the summer of 2000, ended in a raid on Hinkson's house and his arrest in 2002. Referring to the raid, Hinkson later wrote that "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." Hinkson did sue the two officials, and several others, but the suit was dismissed--by Judge Lodge.

As it turns out, President Bush's FBI didn't take too kindly to those, like the militia member at Bundy Ranch, "overheard boasting that he had two agent[s] in his gun sight and could 'take them down.'" A year after Hinkson's arrest, federal officers apprehended members of the Project 7 Militia based in Flathead County, Montana:

On May 6, 2004, several extremist members of the Project 7 Militia were arrested following an extensive investigation into the group by FBI, Bureau of Alcohol, Tobacco, and Firearms, and local police. Investigation had identified leader David Burgert and five other members of the Project 7 Militia as having committed various violations of federal law in furtherance of violent plans targeting law enforcement officers and other government officials. Burgert, along with Tracy Brockway, James Day, John Slater, and Steven Morey, pled guilty to various federal weapons charges, including possession of machine guns and other illegal weapons as well as conspiracy to possess illegal weapons. On November 12, 2004, Burgert received an 87 month prison sentence for his role in the plotting. In early 2005, the four other members who entered guilty pleas received sentences ranging from 18 to 37 months in federal prison. A sixth subject, Larry Chezem, was convicted in a federal trial of conspiracy and was sentenced on September 30, 2005, to 15 months in prison.

In a 2007 New Hampshire episode not covered by the FBI report above, another million-dollar tax cheater turned terrorist when Uncle Sam came for his money. That June, Ed Brown and his wife Elaine, already sentenced to 63 months in absentia for failing to pay his $1 million tab, vowed "that he and his wife would fight U.S. marshals to the death if they tried to capture them." As ABC News reported at the time, the Browns had support from many of the usual suspects:

The couple, however, insists that there is no law that requires citizens to pay income tax.
"There is no law. We looked and looked," Brown told the press.
Brown and his supporters, including Randy Weaver, leader of the 1992 standoff with ATF agents at Ruby Ridge, Idaho, told the press that the government has unlawfully tricked people into believing they have to pay income tax, knowing full well that such a law would be unconstitutional.
"We will defend it to the death. This is 1776 all over again. You cannot tax someone's labor because that is slavery," Brown said.

Ultimately, Ed and his dentist wife ended up in prison for a lot longer than five years after they bunkered down in their 100-acre compound stocked with weapons:

At trial, the couple was found guilty of numerous charges including plotting to kill federal agents during the 2007 standoff; conspiring to prevent federal officers from performing their duties; conspiring to assault, resist or impede federal officers; using or carrying a firearm or destructive device during a violent crime; possessing a firearm or destructive device, being a felon in possession of a firearm; obstruction of justice; failing to appear at sentencing. Mr. Brown was also charged with failing to appear at trial.
Edward Brown was sentence to 37 years, and Elaine Brown, 35 years.

Now, Cliven Bundy, backed by his well-armed well-wishers, claims he "a citizen of Nevada and not a citizen of the territory of the United States." Of course, he is a United States citizen, one who owes the government of his 317 million fellow citizens a million dollars for the privilege of receiving what it is, after all, "food stamps for cows." At best, that makes Bundy a deadbeat. And by threatening federal officials just trying to collect the long overdue payment on the money he owes, Bundy and his Bundy Ranch gunmen make themselves domestic terrorists.
At least according to President Bush's FBI.
UPDATE: For more context on this discussion, it's worth bearing in mind that the FBI's definition of terrorism, whether foreign or domestic, has been essentially unchanged going back to the Clinton administration. In addition, the Bureau distinguishes between terrorist incidents which actually occurred (Oklahoma City bombing) versus those prevented (Hinkson, Project 7 militia). (On a side note, the same FBI report mentioned in the diary classifies abortion clinic bombers and their conspirators as "terrorists," something vice presidential candidate Sarah Palin among others rejected.) The larger point, for the likes of Fox News and its adherents, is that the classification of the Bundy Ranch crowd as "domestic terrorists" has been a bipartisan one.