Atlanta, Georgia -- Watching Eric Rudolph be sentenced to life in prison this week for his terror bombings, I wondered whether he and his followers represent the future of domestic terrorism or the past.
After all, it's been nine years since he bombed the 1996 Olympics. That was little more than a year after Timothy McVeigh bombed the Federal Building in Oklahoma City.
Rudolph's last bombing, of a family planning clinic in Birmingham, Alabama, was in early 1998. Did it mark the end of the era when America's homegrown threat came primarily from right-wing extremists?
The FBI believes Rudolph and McVeigh are part of the past.
Instead, the agency sees a new threat: "The No. 1 domestic terrorism threat is the eco-terrorism, animal-rights movement," said John Lewis, an FBI deputy assistant director and top official in charge of domestic terrorism.
Not so fast, says a monitor of domestic terrorist groups on both ends of the spectrum.
"It is simply ludicrous to describe animal rights and eco-terrorism as the No. 1 threat," said Mark Potok of the Southern Poverty Law Center. He believes those following the paths of Rudolph and McVeigh are still a clear and present danger.
Trying to decide which is the most dangerous domestic threat - far right-wing militants or eco- and pro-animal radicals - is, in some ways, analogous to deciding whether Osama bin Laden or Abu Musab al-Zarqawi poses the biggest international threat.
But if you are the FBI or Department of Homeland Security, your domestic terror priority drives how finite resources are allocated -- especially when so much attention and money is focused on al Qaeda and international terror.
Here's how the animal rights and eco-terrorists made it to the top of the FBI charts.
"There is nothing else going on in this country, over the last several years, that is racking up the high number of violent crimes and terrorist actions, arsons, etc, that this particular area of domestic terrorism has caused," Lewis testified to a Senate committee earlier this year.
Lewis said that from January 1990 to June 2004, "animal and environmental rights extremists have claimed credit for more than 1,200 [attacks], resulting in millions of dollars of damages and monetary loss."
The FBI is worried about mounting rhetoric from the Animal Liberation Front (ALF), whose members regularly break into labs, destroy equipment and threaten scientists; and the Earth Liberation Front (ELF), whose supporters attack SUVs and housing developments.
Consider the words of Jerry Vlasak, a physician who is a well-known activist in the animal advocacy movement in Los Angeles. He said he's not a member of ALF, but makes it his mission to publicize their actions. To Vlasak, anyone who does testing on live animals is a "vivisector."
Vlasak made some incendiary comments at an animal rights conference in 2003. "I think there is a use for violence in our movement," Vlasak was reported as saying.
He called violence morally acceptable at times. "If vivisectors were being killed, I think it would give other vivisectors pause. If there were prominent vivisectors being assassinated, there would be a trickle-down effect ... strictly from a fear and intimidation factor, that would be an effective action."
"You wouldn't need to see too many assassinations" before vivisection declined, he said.
The FBI admits it has had a hard time penetrating ALF and ELF. Actions are usually taken by small groups of people, acting autonomously, and e-mailing or faxing results to people like Vlasak, who publicize the results.
The movement prides itself on this sort of independent cell structure and the lack of central leadership.
But to date, Vlasak notwithstanding, no one has died from any of these attacks. And nothing on the terror scale of Oklahoma City or the 1996 Olympics has been committed, said Potok.
"A single person from the American extreme right managed to murder 168 people in a stroke," he said, referring to Oklahoma City. "There was a Ku Klux Klan plot in the late '90s that contemplated killing 30,000 people."
Potok was referring to a plan by four Klan members to blow up a natural gas refinery near Fort Worth, Texas, in 1997. It never happened.
Potok agreed with Lewis and the FBI that the ALF-ELF movement poses a danger. "I don't mean to diminish their activities. They've caused huge property damage and there is very little question they will kill someone these days."
But he says that -- since Oklahoma City -- 15 police officers have been killed by right-wing extremists and his group has produced a list of some 60 plots by white supremacists and other anti-government radicals during that time - including, of course, Rudolph's bombing campaign.
"It is difficult to understand how the leaders of our major national security organizations can see it this way," Potok said, referring to the FBI's ranking of ALF and ELF as major domestic terrorism threats.
Potok thinks politics is behind the decision: Political pressure from the White House and conservative Republicans toward the environmental movement is, in part, the reason eco-terrorism is now the priority, he said.
"My worry is that, just as in the years running up to the Oklahoma City bombing, ... we will ignore a world of violence emanating from our own extreme right."
For Eric Rudolph's victims, who vented their anger during the sentencing hearing, there is no debate over relative dangers. To them, Rudolph remains the past, present and future of terrorism.
Victims and family of victims offered heart-rending accounts of how their lives had been changed by Rudolph's bombs. Some forgave him. Others cursed him.
Most didn't accept his apology for the Olympic Park bombing. Rudolph refused to apologize for the other bombings - of a family planning clinic and a gay club in Atlanta. His bombings killed two people and severely maimed another.
It was absolutely quiet in the courtroom as Rudolph was led out -- the only sound you could hear came from the shackles on his feet.
Even as he disappeared, the question remained - have we seen the last of his sort and does the future of domestic terrorism hold something new - even something we have not yet experienced?