Attacks like the one that killed two American airmen at Frankfurt Airport last Wednesday will increase because Islamist terrorism is surging, especially among lone wolfs.  The only solution is to defeat extremists and their hosts, which could take decades if we have the will.

American service members such as those murdered last week will continue to be the Islamists’ primary target.  Our troops symbolize America’s foreign policy, which offends many Islamists, and they are the most visible American government representatives at home and abroad.

That Islamists are targeting our troops more frequently at home is an important fact for the House of Representatives to consider during hearings this week on the radicalization of American Muslims.

The Congress should consider evidence that U.S.-based Islamists are waging an escalating campaign of terror, especially against our war-weary armed forces.  Publicly known Islamist incidents include the murders at an Army recruiting office in Little Rock, Ark., and the Fort Hood, Tex., massacre that claimed 13 lives and wounded another 43.

The foiled Islamist cases reported in the press are especially sobering.  Last week, for example, two New Jersey men pleaded guilty to trying to link up with Somali Islamic extremists in an effort to kill American troops abroad.  Other recent cases include the failed Islamist plans to shoot down military aircraft in New York, murder Marines in Virginia, and attack military recruiting stations in Maryland, California, and one in Texas whose perpetrators intended to use weapons of mass destruction.

These incidents combined with the failed Christmas Day 2009 airline bombing and the 2010 attempted Times Square attack should force all Americans to face a stark reality.  The Islamist threat is getting worse, law enforcement can’t stop all the fanatics, and our military—a frequent jihadist target—must do a better job of defending itself.  The final reality is that defeating Islamic extremism is proving to be a very complex, long-term challenge.

First, there is evidence the Islamist threat will get worse at home.  Senior officials including Homeland Security Secretary Janet Napolitano confirm as much.  “Home-based terrorism is here.  And, like violent extremism abroad, it will be part of the threat picture that we must now confront,” Napolitano said.

The Internet is a popular and effective tool used to recruit and radicalize jihadists.  The Frankfurt jihadist’s Facebook profile makes plain his Islamist political leanings and approval of jihad.  He told German police he was inspired to kill the airmen after seeing an online video showing American soldiers raiding an Afghan home and raping a girl, according to the Wall Street Journal.

Social-media jihadist promoter Anwar al-Awlaki regularly posts hate-spewing YouTube videos that are wildly popular.  The American-born cleric, now hiding in Yemen, warns Muslims to “never, ever trust a kuffar [non-Muslim],” praises the attempt by the Detroit-bound airline bomber, and explains why American civilians are legitimate targets.  Al-Awlaki is tied to the Fort Hood massacre and helped inspire Faisal Shahzad, the Times Square bombing suspect.

Recently, other jihadist leaders harnessed Islamist websites to advocate simpler attacks, as opposed to operations such as the 9/11 assaults.  Specifically, al-Qaeda spokesmen Nasir al-Wahayshi and Adam Gadahn called for numerous simpler attacks against soft targets using improvised explosive devices, guns, or even knives and clubs.  Their call may explain why law enforcement is concerned about more lone wolf-type attacks.

Second, law enforcement leaders such as Mitchell Silber, the director of intelligence analysis for the New York Police Department, warn of another reality.  Silber said the number of foiled cases “indicate that radicalization to violence is taking place in the United States, ” which is a major challenge for law enforcement, and foiling these cases could get tougher if their frequency and sophistication increase.

Fortunately, law enforcement successfully stops most jihadist attacks, but not all.  The attempted Detroit airliner bombing and the Times Square incident failed because of jihadist mistakes, not good law enforcement.  But jihadists are learning from their failures, and so is law enforcement.

Reportedly, lessons learned from the 2004 Madrid, Spain, and 2007 Mumbai, India, attacks helped New York officials stop several plots directed against New York’s subway system.  Federal agents also applied lessons from past attacks to foil a jihadist case involving six ethnic Albanian Muslim men who planned to massacre American soldiers at Fort Dix, New Jersey .

Federal officials were tipped off by the wannabe killers’ poor terror tradecraft.  The jihadists made a videotape of them calling for “jihad” and practicing with assault weapons and then naively took the tape to a store for copying.  The store owner alerted the authorities who opened the investigation.

The conspirators also insisted on purchasing illegal fully automatic weapons.  Both tradecraft errors were widely publicized and likely won’t be repeated by the next jihadist group.

The third reality is that our military will continue to be a popular jihadist target.  That fact explains the significant increase in security around military installations to include strict procedures for accessing bases, and more barriers and guards.  The Pentagon also requires troops take annual anti-terrorism classes.

But the military’s jihadist problem has an internal component, as illustrated by the Fort Hood massacre.  Army Maj. Gen. Robert Radin, the leader of his service’s Internal Review Team, said, “We must efficiently and effectively transform how we look at protecting the force.”  Unfortunately the Army’s report labels the attack a “tragedy” rather than an Islamist terrorist attack, a fatal flaw.

Sen. Joe Lieberman (I.-Conn.) rightly faults the Army for failing to explain “that we are threatened by violent Islamist extremism and that an Army major who made public statements supportive of this murderous ideology was not stopped.”  Lieberman called on the Pentagon and the FBI to “deal directly and effectively with the deadly threat that violent Islamist extremism poses to our service members.”

It would also be refreshing if President Obama admitted we have an Islamic problem, but given his track record, that is doubtful.

Finally, the jihadist threat could get worse if the unrest sweeping the Mideast results in more radicalized Islamic governments that harbor terrorists.  That is why defensive measures alone are insufficient to remove the Islamist scourge. 

The only way to stop Islamist terrorism is to defeat it at the core.  The radicals that spew their hatred must be eliminated and regimes that harbor them must stop doing so or be removed.

Congress can help by insisting the Pentagon and law enforcement honestly identify the root cause of much of the terrorist threat—Islamic extremism—and provide public servants the laws and methods to eliminate the radicals and their sponsors.