Two of the areas with significant potential or actual threats are the Strait of Hormuz and the South China Sea. The Strait of Hormuz, as has been mentioned, is very important from a strategic and economic perspective. Oil is crucial to the economies of many nations, including, perhaps especially, the United States, and this makes the strait even more vital. There has been conflict over it in the past. During the Iran-Iraq War, Iranian, Iraqi, and American naval forces all engaged in combat within, and sometimes without, the Persian Gulf, to which the strait leads, and shipping was even attacked near the strait. The conflict demonstrated that mines, shore-based missiles, aircraft, and warships (including submarines) all could be used to effectively attack shipping in the strait and around it.
Currently, the main threat is still Iran. Its navy can attempt to cut off the strait. This would have a major economic impact and an impact on shipping, and would most definitely lead to a major naval engagement, as the United States and other nations would not tolerate it. Iran also has the will to do it if they feel that it is necessary, which makes this threat to security more credible.
The strait is also threatened by terrorism, as it is in the Middle East, which has been a hub for terrorism recently due to the rise of radical Islam. There is the potential for there to be shipping attacked by maritime terrorists, and it has been done in the region. Piracy also remains an issue, although it is not as significant as it used to be.
The South China Sea has as the greatest threat to its security the potential for armed conflict over islands, and possibly chokepoints, within and bordering it. Islands, such as the Spratly Islands, are or may potentially be sitting on large quantities of oil. Oil is in greater demand than ever, and crucial to the economies of many nations. China especially requires it, as domestic oil is short on supply. This has led to multiple claims over the various islands. This is partly due to the Exclusive Economic Zones and Continental Shelf areas which would be claimed by whoever claims the respective islands due to the Law of the Sea Treaty. China, or another country, may attempt to seize the islands by force, leading to what potentially could erupt into a major armed conflict; this is an obvious threat to maritime security. Piracy is also high in the region, and thus remains a threat as well, but it pales in comparison to a potential armed conflict.
Despite the threat in the South China Sea, ultimately the greater maritime security threat is in the Strait of Hormuz. The chances of conflict are greater due to the nature of the nation most likely to initiate a conflict. Since lots of oil transits the strait, it has profound importance and the impact on the world of a conflict would be considerable, as would the impact on shipping. The threat of terrorism is also far more significant in the region than in the South China Sea. The degree of the impact of potential maritime security threats in the Strait of Hormuz, combined with the greater likelihood of major threats becoming reality, means that one must consider it to be subject to a greater maritime security threat than the South China Sea.
Straits and other significant sea lanes and choke points are very important to the world. This is the case from both an economic and strategic aspect. Large amounts of trade and shipping transit these areas every year. This results in conflict and the potential for conflict, along with other forms of threats, which in turn makes these areas of interest to those studying maritime security.
