Homeland security consists of all military activities aimed at preparing for, protecting against or managing the consequences of attacks on American soil, including the CONUS and US territories and possessions. It includes all actions to safeguard the populace and its property, critical infrastructure, the government and the military, its installations and deploying forces.

While other definitions are certainly possible, the merit of the definition just presented is that it is clear about homeland security's focus on military activities, as distinct from the activities of civilian organizations, its geographic specificity and the potential targets it seeks to protect.

The constitutional and legal context
The fundamental justification and broader context for homeland security activities can be found in the Preamble; Article I, Section 8; and Article IV, Section 4, of the Constitution of the United States. The Preamble includes the basic "insure domestic tranquility" and "provide for the common defense" justifications:

[In] Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defense, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity.

Article I, Section 8, elaborates on the circumstances in which the military might be domestically employed:

Congress shall have Power {A133} to provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections, and repel Invasions.

And Article IV, Section 4, expands on this authority:

The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them {A133}against domestic Violence.

Federal laws provide the specific mechanisms for federal (including military) support to civil authorities, particularly in the context of "civil emergencies":

The modern authorization for Federal support to civil authorities is based on the Robert T. Stafford Disaster Relief and Emergency Assistance Act (P.L. 93-288) and the Economy Act. The former enables the Federal Government to "provide assistance to US states, territories, and possessions to alleviate suffering and mitigate damage resulting from major disasters and civil emergencies." The latter empowers Federal agencies to provide routine support to each other under certain conditions if reimbursed. (Grange and Johnson, 1997.)

Homeland security activities are even more apparent in the warrant given the Department of Defense (DoD):

[DoD] maintains and employs the armed forces to:

• Support and defend the Constitution of the United States against all enemies, foreign and domestic.
• Ensure, by timely and effective military action, the security of the United States, its territories and areas vital to its interests.
• Uphold and advance the national policies and interests of the United States.
• Safeguard the internal security of the United States. (DoD, 1987, pp. 17-18.)

The strategic context
The strategic context for homeland security is described well in the report of the National Defense Panel (NDP):

The United States enters the new millennium as the preeminent political, economic and military power in the world. Today we are in a relatively secure interlude following an era of intense international confrontation. But we must anticipate that future adversaries will learn from the past and confront us in very different ways.

We can safely assume that future adversaries will have learned from the Gulf War. It is likely that they will find new ways to challenge our interests, our forces, and our citizens. They will seek to disable the underlying structures that enable our military operations. Forward bases and forward-deployed forces will likely be challenged and coalition partners coerced. Critical nodes that enable communications, transportation, deployment, and other means of power projection will be vulnerable.

Our domestic communities and key infrastructures may also be vulnerable. Transnational threats may increase. As recently stated by [Defense] Secretary [William S.] Cohen, the proliferation of nuclear, chemical, and biological weapons and their delivery means will pose a serious threat to our homeland and our forces overseas. Information systems, the vital arteries of the modern political, economic, and social infrastructures, will undoubtedly be targets as well. The increasing commercialization of space makes it feasible for state and nonstate actors alike to acquire reconnaissance and surveillance services.

In short, we can expect those opposed to our interests to confront us at home and abroad--possibly in both places at once--with asymmetrical responses to our traditional strengths. (National Defense Panel, 1997, p. ii.)

Importantly, the report implies that adversaries may use a range of unconventional weapons (WMD, cyber attacks, etc.) to target both theater forces and the US homeland in future major theater wars (MTWs).

National Security Strategy
In October 1998, the White House released an updated version of the US National Security Strategy (NSS) titled A National Security Strategy for a New Century, which identified weapons of mass destruction (WMD) and terrorism as two concerns that transcended national borders. Although stressing WMD as the greatest potential threat to global stability, the report also cited the increasing likelihood of an unconventional attack on the US or its people:

Potential enemies, whether nations, terrorist groups, or criminal organizations, are increasingly likely to attack US territory and the American people in unconventional ways. Adversaries will be tempted to disrupt our critical infrastructures, impede continuity of government operations, use weapons of mass destruction against civilians in our cities, attack us when we gather at special events, and prey on our citizens overseas. The United States must act to deter or prevent such attacks and, if attacks occurs [sic] despite those efforts, must be prepared to limit the damage they cause and respond decisively against the perpetrators{A133}.(White House, 1998d, pp. 1 and 6-8.)

The solution, in the conception of the National Security Strategy, is a broad, national effort that relies on interagency efforts at the federal level and a program that knits these federal capabilities together with local and state capabilities.

National Military Strategy
The most recent version of the National Military Strategy (NMS) was published in 1997, prior to the current version of the National Security Strategy; this may account for its relative inattention to the issue of homeland security, although it does touch on such threats as state and nonstate actors and asymmetric warfare against the United States. For example, the NMS states:

Some state or nonstate actors may resort to asymmetric means to counter the US military. Such means include unconventional or inexpensive approaches that circumvent our strengths, exploit our vulnerabilities, or confront us in ways we cannot match in kind. Of special concern are terrorism, the use or threatened use of WMD, and information warfare. These three risks in particular have the potential to threaten the US homeland and population directly and to deny us access to critical overseas infrastructure{A133}.. We must increase our capabilities to counter these threats and adapt our military doctrine, training, and equipment to ensure a rapid and effective joint and interagency response. (Joint Chiefs of Staff, 1997.)

The Army Strategic Plan
Among the vital interests identified in the 1999 Army Strategic Planning Guidance (ASPG) is "the sovereignty of the United States, to include the safety of the population and the security of critical physical and information infrastructure." The ASPG envisions a threat environment that contains both transnational and asymmetric threats to the nation. Transnational threats to the homeland include enemies who "use the international telecommunications system to synchronize an impressive set of capabilities to delay or disrupt our military operations or attack the US homeland," while asymmetric threats include terrorism, WMD and information warfare against the US National Information Structure (NII) or Defense Information Structure (DII).

In light of these emerging threats, the ASPG accordingly has a revised set of mission areas that now explicitly includes support to homeland security.

Thus, although each of the policy documents touches on many of the threats that have led to consideration of a homeland security mission, neither the National Security Strategy, the NMS, nor the Army Strategic Plan clearly define homeland security as a critical, separate mission consisting of specific task areas or place it in the context of the current defense planning framework of two nearly simultaneous major theater wars (MTWs).

The domestic political context
The response to these emerging threats was three major programs: combating terrorism, enhancing domestic preparedness against WMD, and critical infrastructure protection.

Within the Clinton administration, increasing concern about the proliferation of WMD led, on November 14, 1994, to Executive Order 12938, in which the president declared a national emergency. The Executive Order then went on to enumerate the responsibilities of the departments and agencies in nonproliferation activities. On November 12, 1998, the President extended the national emergency and amended the original executive order to broaden the types of proliferation activities covered.

Two Presidential Decision Directives (PDD) provided subsequent policy guidance for combating terrorism and WMD:

• PDD 39, June 21, 1995, directed that efforts to combat terrorism include reducing vulnerabilities to terrorism, deterring and responding to terrorist acts, having capabilities to prevent and manage the consequences of terrorist use of NBC weapons, including those of mass destruction.
• The Combating Terrorism directive, PDD 62, May 22, 1998, "highlighted the growing threat of unconventional attacks against the United States and detailed a new and more systematic approach to fighting terrorism by bringing a program management approach to US counterterrorism efforts." The directive also established the office of the National Coordinator for Security, Infrastructure Protection and Counter-Terrorism, which oversees policies and programs in counterterrorism, protection of critical infrastructure and preparedness and consequence management for WMD.

In a similar vein, concern grew about threats to the nation's physical and electronic critical infrastructures. "Critical Infrastructures" are defined as "those physical and cyber-based systems essential to the minimum operations of the economy and government. These systems are so vital that their incapacity or destruction would have a debilitating impact on the defense or economic security of the United States." (White House, 1998b; Executive Order, 1996.)

	Thinking Point
	Compare possible repercussions of the various types of potential attacks against domestic targets in the US. Consider not only loss of life, but long-term health, economic, security and political issues.

Chartered a year earlier, the President's Commission on Critical Infrastructure Protection reported in October 1997 that "While we see no electronic disaster around the corner, this is no basis for complacency. We did find widespread capability to exploit infrastructure vulnerabilities. The capability to do harm--particularly through information networks--is real; it is growing at an alarming rate; and we have little defense against it."

The commission accordingly called for a national effort to assure the security of the nation's increasingly vulnerable and interconnected infrastructures. And in May 1998, PDD 63 was released, building on the Commission report.