Criminology

Murray Rothbard, an American intellectual and Libertarian, stated that there is a just war existing when people are fighting against a coercive dominion of another group of people. It also exists when people are trying to overthrow an already existing domination. There is no however a just war when people try to rule over or dominate another people or try to retain an already existing dominion. The Just War Theory has two sets of criteria, the right to go to war (jus ad bellum), and the right conduct within war (jus in bello). There is only a right to go to war when the following are met
Just Cause. In 1993, the US Catholic Conference stated Force may be used only to correct a grave, public evil, i.e., aggression or massive violation of the basic human rights of whole populations.

Comparative Justice. One party must suffer more than the other. In other words, the sufferings endured by one party must outweigh that of another party. However, this principle is quite questionable as it can be used by some clever organizations to their advantage.

Legitimate authority. Those who can wage wars are only the duly constituted public authorities. Even just causes cannot be served by actions taken by individuals or groups who do not constitute an authority sanctioned by whatever the society and outsiders to the society deem legitimate.
Right intention. Only a truly just cause is acceptable ground for waging wars. Furthermore, the war must be fought only because and for that certain cause. An example of a right intention is correcting a suffered wrong. Material gain or maintaining economy is not a valid and acceptable reason for waging wars.

Probability of Success. In cases where disproportionate measures are needed to succeed, arms may not be used. This is also true for a futile cause.

Last resort. All non-violent options must first be exhausted before the use of force can be justified.
Proportionality. The expected evils or harms of a war must be in proportion to the anticipated benefits. This is also known as the principle of macro-proportionality.

There are also guidelines on how to act during just wars and they are as follows
Distinction. The acts of war should be directed only towards enemy combatants. Non-combatants and innocent individuals must not be involved or harmed in any way.

Proportionality. An attack cannot be launched on a military objective in the knowledge that there would be excessive incidental civilian injuries in relation to the anticipated military advantage.
Military necessity. There should be minimum force applied in a just war. The goal of any attack or action is to help the military defeat the enemy. It must be an attack on a military objective and not an act to harm civilians or destroy civilian properties. Should there be harm or destruction against civilians, it should not be excessive in relation to the concrete and direct military advantage anticipated. The deaths of civilians are justified only if they are unavoidable victims of a deliberate attack on a military target.

Having stated these, it can be deduced that the war on terror is a just war. It has a just cause with the right intention, given by someone in authority. Also, it is already needed to protect the citizens. It is no longer right and acceptable to allow terrorists ruin the lives and properties of innocent individuals. Even if they claim that they have a mission to fulfill or a message to deliver and that they needed to do such acts, still it is not just and totally a violation against human right. With what these terrorists did and are still capable of doing, the military is left with no choice but to wage a war against them. Remember that the military is condemning the act of terrorism and not the Arabs or any race for that matter. Fighting terrorism would only cease to be just if it violates any of the above-mentioned principles. If it was done solely for the personal gain or revenge, if it does not consider innocent lives and would just be aggressive in killing the enemies. These are the only grounds for a war against terror to be not considered as just. Apart from these, the war against terrorism is a necessary action to protect and preserve precious lives and properties and to put an end to this worldwide violence and terror.

USA Patriot Act
The USA Patriot Act signed on October 26, 2001, more than a month after the 911 attack, is an abbreviation for its title Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism.