The President of the United States has no greater responsibility than protecting the American people from threats, both foreign and domestic. In taking his oath of office, the President swears to "preserve, protect, and defend the Constitution of the United States," the Preamble of which recognizes providing for the "common defense" as a top priority. Now Congress must make its voice heard on a key issue of national security and bring to a vote support for President George W. Bush's strategy for pursuing the war on terrorism in the way that he, as commander in chief, deems necessary.

While there has been little argument regarding the use of armed force in Afghanistan to retaliate against an act of aggression, opposition has risen regarding a preemptive strike against Iraq and, in general, to the concept of preemption as a national security tool. However, taking action to prevent a strike against America and its allies is also clearly justifiable because the following principles apply:

Principle #1: The right to self-defense is codified in customary international law and in the Charter of the United Nations.

Principle #2: The right of "anticipatory self-defense" allows for preemptive strikes.

Principle #3: The United States government, alone, has the authority to determine what constitutes a threat to the United States and what should be done about it.

Principle # 4: The President as commander in chief has the authority to use America's armed forces to "provide for the common defense."

Learning from the September 11 Attacks. Not only is the President justified in applying preemptive military force to fight the war on terrorism, but not doing so would ignore the lessons learned since the September 11 attacks that must be taken into consideration when future action against terrorists and terrorist states is considered.

Lesson #1: Deterrence alone is not sufficient to suppress aggression.

Lesson #2: Attacks can occur with little or no warning.

Lesson #3: The use of a weapon of mass destruction (WMD) is reasonably likely.

Lesson #4: A deadly synergy is created when state and non-state actors work together.

Lesson #5: The future envisioned by America's enemies is incompatible with U.S. security.

The Case Against Iraq. When these lessons are applied to Saddam Hussein's Iraq, it is clear that action must be taken now. Iraq poses a direct threat to the United States and its interests and to peace and stability throughout the world. Saddam's hostility to U.S. interests, proven intent to act against those interests, history of WMD acquisition, pursuit of WMD, history of using WMD to achieve foreign policy objectives, and ties to international terrorists all make him uniquely dangerous. The foregoing five lessons apply to Iraq in the following ways:

Applied Lesson #1: Warnings have not deterred Iraq from overtly hostile actions that threaten the United States and its interests.

Applied Lesson #2: Iraq's ongoing development of weapons of mass destruction means that the United States or its interests could be targeted with little or no warning.

Applied Lesson #3: Saddam Hussein's history of using WMD demonstrates the likelihood that he will use them in the future.

Applied Lesson #4: Iraq's aggression and ties to international terrorism comprise a deadly combination that must be confronted.

Applied Lesson #5: Iraq's blatant disregard for its 1991 cease-fire agreement makes it clear that its vision of the future is incompatible with America's security.

Next Steps. Since September 11, 2001, President Bush has shown remarkable leadership, and Congress generally has supported him in his efforts to ensure the security of the nation. It is now time to move beyond efforts to dismantle the terrorist infrastructure that directly enabled the attacks that claimed the lives of thousands of innocent Americans and to take bold steps to ensure that such horrendous acts do not take place in the future. To this end,

• The President must remain steadfast in his approach to Iraq. The President is moving thoughtfully and deliberately, making his case to Congress, America's friends and allies, and the American people. He must convince Congress that only a resolution that gives him ample flexibility to prosecute the war on terrorism effectively will be acceptable.
• Congress should vote now to show its support for the President. Congress has a responsibility to bring this critical issue to a vote. U.S. citizens deserve to know where each of their elected representatives stands in supporting the President's use of whatever means he deems necessary to defend the nation from Iraqi weapons of mass destruction.

Conclusion. Now is the time to take decisive action to disarm Saddam Hussein. President Bush began this process with his address to the United Nations General Assembly on September 12. However, if the U.N. balks in addressing Iraq's flouting of more than 16 of its resolutions, the President still has full legal authority, from the U.N. as well as Congress, to take whatever actions may be necessary.

On September 11, 2001, Americans came to a new understanding of the nation's vulnerability and the nature of the threats that now confront the nation. No longer can the United States wait passively while regimes foment terrorism, build weapons of mass destruction, and propagate hatred for America. The war on terrorism may be long and difficult, but the President has the authority and responsibility to use whatever means he deems will be effective to ensure the security of the United States and the American people.

--Jack Spencer is Policy Analyst for Defense and National Security in the Kathryn and Shelby Cullom Davis Institute for International Studies at The Heritage Foundation.