Some of the cases of illegal uses force include the following & #8230; Clandestine Support:

The use of force is considered illegal when a state is involved in clandestine support in a conflict involving two other countries. Under the contemporary international law, a state that is a third-party to a conflict should always remain neutral (Slomanson, p. 473). When the third-party state supports one of the warring parties in the conflict by providing military support its use of force is regarded as illegal. The use of clandestine support by a third-party state to support one of the warring parties is an illegal use of force.

Low-intensity Conflict:

Under the contemporary international law, the spectrum of the use of force is within the categories of small-scale hostilities and all-out war. Low-intensity conflicts started to emerge with the ongoing frequency in the post-Cold War period. While there have been numerous wars in the 20th Century, there have been low-intensity conflicts during the same period. Low-intensity conflicts are those with lesser magnitudes of destruction and deaths for the affected individuals. Based on the United States military definition of low-intensity conflict, it usually involves extended struggles of competing ideologies and principles.

The use of force in low-intensity conflicts can be regarded as illegal because it's usually below conventional war though beyond the peaceful competition between states. The conflicts are waged through a combination of political, informational, military, and economic instruments. The use of force in these types of conflicts is largely considered as illegal because of the nature of the war or conflict since they are below the conventional war and above peaceful competition.

Necessity for Powerful States:

Actually, more powerful states especially European countries established convenient justifications for their aggressive uses of force (Slomanson, p. 475). These powerful states stated that the use of force was the only efficient method for enforcing international law. This resulted in the limitless use of force that became the focus of national policies for many leaders and states as a means of preserving national security. However, this self-righteous justification by powerful states about their use of force is illegal since it's only used as a means of preserving a country's national interests rather than the peaceful co-existence of nations.
This concept proves to be illegal due to the numerous aggressive natures of certain leaders like Hitler to stimulate military conflicts based on the convenient justification. Due to the consideration that the use of force is a necessity for powerful states, many military conflicts have emerged after the end of the Second World War. These military conflicts have been low-scale military combat, declared or undeclared wars, low intensity conflicts, and civil or international wars with severe consequences.

Conclusion:

The use of force has become an important aspect under contemporary international law especially regarding its legitimacy. Consequently, there are various cases that have emerged that present the legal and illegal uses of force in the modern society.

Work Cited:

Slomanson, William R. "Chapter Nine - Use of Force." Fundamental Perspectives on International Law. 6th ed. Boston. MA: Wadworth, Cengage Learning, 2011. Cengagebrain.com. CengageBrain, 2011. Web. 5 Dec. 2011. .