(CNN) -- Americans watched this week as U.S. interests abroad became targets of Muslims enraged over a film mocking their religion. It was a storyline featuring familiar characters in the so-called war on terror, but some experts say the narrative may be overplayed.
Though radical Islam and Western interests are commonly the primary subjects of stateside conversation when it comes to terror, domestic terrorists pose significant threats to the homeland, experts say, and the U.S. needs to do more to safeguard itself from the threat within.
A handful of recent events -- including the deadly rampages at a Sikh temple in Wisconsin and an Aurora, Colorado, theater -- have left communities in grief and raised additional questions about whether we're paying enough attention to domestic terrorism following the September 11, 2001 attacks.
"9/11 has set the threshold for what terrorism is in the minds of many Americans, and if domestic terrorism lacks the magnitude, it must not be terrorism," said Daryl Johnson, a former counterterrorism expert at the Department of Homeland Security. Johnson says he left DHS in 2010 out of frustration.
According to Johnson, many in the government have taken a myopic view based on the severity and magnitude of 9/11, leaving them unable to move beyond the threat posed by jihadist groups.
Heidi Beirich, director of the intelligence project at the Southern Poverty Law Center, a civil rights group, claims the domestic threat cannot be overlooked after the shootings at the Sikh temple.
"Domestic terrorism is as much a threat as foreign terrorism. The government needs to get serious about this," she said.
While the feds have said that the Aurora incident was not a terrorist act and the FBI continues to investigate whether the shooting at the Sikh temple was an act of domestic terrorism, these incidents have drawn attention to domestic threats.
The FBI's shorthand definition of domestic terrorism is "Americans attacking Americans based on U.S.-based extremist ideologies."
According to a May 2012 congressional research service report, counterterrorism efforts have been shaped largely in response to acts of foreign terrorism. The emphasis of counterterrorism policy since 9/11 has been on jihadist terrorism, despite the fact that domestic terrorists have been responsible for more than two-dozen incidents since 9/11, the report states.
The congressional report points to data collected by the National Counterterrorism Center's Worldwide Incidents Tracking System, which publicly lists 35 terrorist incidents occurring in the United States between the beginning of 2004 and September 2011. Of those, 25 were linked to domestic terrorists.
Experts say the domestic threat can no longer be pushed to the background.
A September 2011 survey by the New America Foundation and Syracuse University's Maxwell School of Public Policy examined 114 cases of non-jihadist terrorist acts in the 10 years following 9/11. In comparison, they found 188 cases of Islamist terrorism in the U.S. for the same period. Some of the cases examined involved plots that were foiled and unsuccessful.
Examples of domestic terror cases since 9/11 include a 2001 plot by Earl Krugel, a member of the Jewish Defense League, to blow up the office of Arab-American congressman Darrell Issa and the King Fahd mosque in Culver City, California and the February 2010 suicide attack by Andrew Joseph Stack III, where he flew his airplane into the IRS building in Austin, Texas killing one other person and injuring many more.
According to the survey, the 114 cases of domestic terrorism do not represent a complete survey of non-Islamist terrorist cases. Keeping track of domestic terrorism incidents is far more difficult than tracking incidents of jihadist terrorism. Jihadist terror cases are nearly all tried under anti-terrorism laws or statutes dealing with "material support" to terrorist groups. Domestic terrorism cases on the other hand are often tried under an array of other statutes, from weapons and explosives violations, property destruction and arson to "seditious conspiracy," the survey stated.
These ideologies behind the domestic attacks encompass a wide range of groups. On the left, you have anarchists and some Communist factions. On the right, there are white supremacists and sovereign citizens, participants of which do not recognize U.S. currency, taxation or city, state or federal laws. There are also more single-minded groups that include some animal rights, environmental and anti-abortion outfits.
While left-wing groups have frequently vandalized property and committed arson, right-wing groups present a more deadly threat given their affinity for hoarding weapons and explosives, according to Johnson, who now runs a private security consulting firm.
"What worries me is the fact that our country is under attack from within, from our own radical citizenry," Johnson said. "Yet our leaders don't appear too concerned about this. So, my greatest fear is that domestic extremists in this country will somehow become emboldened to the point of carrying out a mass-casualty attack because they perceive that no one is being vigilant about the threat from within."
Despite the threat right-wing groups pose, intelligence-collection efforts have not received the same attention as foreign threats, according to the congressional report.
The Southern Poverty Law Center has documented a dramatic growth in the number of militias and hate groups operating in the U.S. over the past decade. Currently, there are more than 1,000 hate groups in the United States, according to the center, which says it was monitoring the alleged Sikh temple gunman for years before the attack.
"They are like little sitting time bombs," Johnson said.
In the aftermath of the Wisconsin shooting, online forums among radical right-wing hate groups have ignited with vitriolic messages.
"Take your dead and go back to India and dump their ashes in the Ganges, Sikhs," Alex Linder, a neo-Nazi who operates the racist website Vanguard News Network, wrote on his forum. "You don't belong here in the country my ancestors fought to found, and deeded to me and mine, their posterity. Even if you came here legally, and even if you haven't done anything wrong personally. Go home, Sikhs. Go home to India where you belong. This is not your country, it belongs to white men."
According to Johnson, there are certain poisonous belief systems in this country that have a history of violence.
"They have the capability and the intent. All they're lacking is the catalyst. And there lies the problem," he explained, adding he believes the government needs to look closer at whether a group is on a trajectory to violence.
Any counterterrorism efforts should be proactive rather than reactive. But Johnson claims the current approach is a hands-off one unless the group is engaging in some criminal activity.
"These groups proliferate like mushrooms after the spring rain," he said. "Criminal activity will certainly follow."
He explained that the election of President Barack Obama has been a huge factor in the proliferation of extremist groups at home.
"It's their worst nightmare come true," he said.
The election of the first black president sent shockwaves through many of these right-wing groups who feel threatened by the changing demographics of the nation. Johnson predicts that if Obama wins a second term, there will be more violent attacks by these domestic groups.
Yet there remain massive gaps in domestic counterterrorism efforts, according to Johnson.
Following a 2009 Department of Homeland Security report authored by Johnson on the growing threat posed by right-wing extremist groups, the domestic terrorism unit under the DHS was disbanded because of pressure from the political right-wing, claims Johnson.
Conservative media political analysts like Michelle Malkin, Sean Hannity, Lou Dobbs and Rush Limbaugh criticized the report as an attempt to demonize the right. It also drew criticism from some members of the military because the report claimed right-wing extremist groups recruited veterans and soldiers.
After the release of the report, a number of draft reports were put on hold or canceled entirely,according to Johnson. Products that concerned domestic terror were subject to greater scrutiny and stalled in an effort to kill the work, said Johnson.
"These restrictions were selectively applied to work on domestic terrorism than to jihadi terrorism," he said, adding that his frustration led him to quit a year later.
Resources devoted to domestic counterterrorism have been cut, and there is now only one intelligence analyst at the DHS looking at domestic terrorism. That's compared to five after 9/11, according to Johnson.
There is also a void in training officials to recognize these threats, Johnson claims. While the DHS has implemented some training in the last year -- nine sessions so far -- they have not been sufficient, Johnson explained.
In his time there, the DHS ran up to 10 sessions per month. Training sessions by other agencies remain limited in scope, Johnson explained. The FBI, for example, focuses mainly on the sovereign citizens groups, he said.
In a 2008 meeting between the counterterrorism units of the FBI and DHS, it was apparent the FBI did not have the proper information to investigate, according to Johnson.
"They didn't even appear aware of the resurgence of militias and extremist groups," Johnson said.
DHS spokesman Peter Boogaard said he could not comment on these assertions as they involve classified information. But in a written statement he said the DHS "protects our country from all threats, whether foreign or homegrown, and we know that violent extremism is neither constrained by international borders, nor limited to any single ideology.
"As such, DHS continues to work with its state, local, tribal and territorial partners to prevent violence that is motivated by any extreme ideological beliefs. This includes training law enforcement to recognize behaviors and other indicators associated with violent criminal activity as well as briefings, products, case studies, and information sharing on violent extremist threats," the statement said.
In an April 2005 report titled "10 Years After the Oklahoma City Bombing: the Department of Homeland Security Must Do More to Fight Right-Wing Terrorists," Rep. Bennie Thompson, then-head of the House Committee on Homeland Security, called for a renewed effort to catalog the risks posed by right-wing domestic terrorists. In the report, he slammed the DHS for omitting the threat of right-wing terror threats in a long-range planning document.
"Democratic members of the House Committee on Homeland Security are very concerned that this oversight demonstrates DHS administrators are not adequately considering right-wing domestic terrorist groups that are focused on attacking America in order to further their political beliefs," he wrote.
The government is also inconsistent in how it categorizes domestic extremist groups. While the federal government lists groups such as al Qaeda and Hezbollah as terrorist organizations, there is no such practice of designating any domestic groups as terrorist organizations.
According to the State Department's Bureau of Counterterrorism, the secretary of state had designated 49 foreign terrorist organizations as of January 2012. The FBI and Department of Justice do not generate an official list of domestic terrorist organizations.
The lack of such a list may make it difficult to assess the scope of domestic terrorism and evaluate trends and counterterrorism efforts. It also creates the misconception that terrorism comes only from abroad.
However, advocacy groups like the American Civil Liberties Union object to such categorizations, arguing that labeling some domestic groups as such would discourage free speech and expression.
Michael German, an expert at the ACLU who has also worked as an FBI agent for 16 years, argued that any characterization of groups that are not engaged in criminal activity is problematic.
The listing of foreign terrorists has already been problematic, and the replication of such a methodology would not be the correct approach. A sound approach should target individuals, not groups, he explained.
"It's not about the label," German said.
Regardless of whether extremists groups are put on watch lists, the need for certain data is critical for effective counterterrorism efforts. The congressional research service report claims that until 2005, the FBI used to regularly release a report that cataloged annual terrorist plots and in Mafraq, Jordan,incidents in the United States.
Arguably, the discontinuation of such reporting makes it difficult for policymakers to forge effective policies because it becomes more difficult to compare the levels of domestic terrorist activity against jihadist activity.
Experts including Johnson and Beirich say it may be time to take a more informed approach and look more closely at current security gaps.