Terrorism seems to have become a regular part of modern life. Hijackings, bombings and assassinations across different continents may seem like isolated incidents, but they reflect an easy reliance on violence as a way to promote social, political and religious change. They are elements of a pervasive “end justifies the means” philosophy being followed to its most perverse conclusions.

Democratic governments, accustomed to dealing within a legal structure, often find it difficult to deal with criminals and terrorists who operate outside of the law. Yet deterrence is just as much a part of justice as proper enforcement of the laws.

According to FBI Director James B. Comey, the FBI’s investigation of the San Bernardino, California attack revealed that the perpetrators were homegrown extremists inspired by foreign terrorist groups. They were not directed by official groups and were not part of any terrorist cell or network. FBI investigators have said that Farook and Malik had become radicalized over several years prior to the attack.

Farook and Malik had traveled to Saudi Arabia in the years prior to attack. The couple had amassed a large stockpile of weapons, ammunition and bomb-making equipment in their home.

Democratic governments that do not deter criminals inevitably spawn vigilantism as normal, law-abiding citizens, who have lost confidence in the criminal justice system, take the law into their own hands. A similar backlash is beginning to emerge as a result of the inability of Western democracies to defend themselves against terrorists.

But lack of institutional resolve is only part of the problem. Terrorists thrive on media exposure, and news organizations around the world have been all too willing to give terrorists the publicity that they crave. If news media gave terrorists the minuscule coverage their numbers and influence demanded, instances of homegrown terrorism would decline. But when hijackings and bombings are given prominent media attention, would-be criminals see a reaction that they feel justifies their actions.

When terrorists attack, America should not view them as criminals but as foreign soldiers who attempt to threaten the very existence of the American government. Whether terrorist groups have the firepower and strategic vision to literally undermine the U.S. government is not the issue. The issue is how to deal with an unconventional type of military aggressor.

Terrorists are not common criminals to be tried in American civil courts. They are military targets who must be stopped since they are armed and military enemies of the American government.

In the same way that it takes conventional armies time and experience to learn how to combat guerilla enemies, Western governments and media outlets are now struggling to comprehend the rules for warfare and media coverage in the case of terrorism. Diplomatic efforts have failed to convince Middle East governments to help the United States in bringing terrorist groups to justice. Meetings and negotiations simply cannot strike fear in terrorist’s hearts. For example, Pakistan knew that Osama Bin Laden had been hiding in Abbottabad. According to a 2014 CNN report by National Security Analyst, Pete Berger, the Inter-Services Intelligence, Pakistan’s military-operated intelligence organization, included a special position that handled bin Laden.

“[The desk] was operated independently, led by an officer who made his own decisions and did not report to a superior,” the report said. “He handled only one person: bin Laden.”

Although diplomatic relations with our allies has been the primary means used by the United States against terrorism, we should consider what other means may also be appropriate. In the past, American leaders have responded to military aggression in a variety of ways short of declaring war.

The U.S. Constitution grants the following powers to Congress: “To define and punish piracies and felonies committed on the high seas, and offenses against the law of nations; To declare war, grant letters of marquee and reprisal, and make rules concerning captures on land and water.” Terrorist acts fall into at least two of the congressional provisions for dealing with attacks on the nation. They are: (1) to punish offenses against the law of nations, and (2) to declare war.

Military and political leaders must follow a strategy of hunting down small groups of well-armed and well-funded fighters who hide within a host country. We must also develop a political strategy that will allow us to work within a host country.

Through diplomatic channels we must make two responsibilities clear for any host country. Either they catch and punish the terrorist groups themselves as civilian criminals, or they extradite the terrorists and give them up to an international court for trial. If the host country fails to act on these two requests, we should make it clear that we see them in complicity with the terrorist groups. By failing to exercise their civil responsibility, they leave themselves open to the consequences of allowing hostile military forces within their borders.

We must recognize terrorism as a new type of military aggression which requires governmental action. We are involved in an undeclared war and Congress and the president must take the same sorts of actions they would if threatened by a hostile country. This is necessary to deter further terrorist aggression in this decade. American citizens are tired of being military targets in an undeclared war.