The U.S. Navy announced April 24 that it had concrete plans to re-establish the long-dormant 4th fleet. Based out of Mayport, Florida, the U.S. 4th fleet will be responsible for naval operations in Central and South America and the Caribbean effective July 1, 2008.

Although the United States has maintained a constant and notable naval presence in the region recently, this move can be seen as an important geopolitical indicator of the evolving nature of U.S. naval superiority and its interactions with an increasingly active region.

The United States established the 4th fleet in 1943 to help establish regional security in the Western Hemisphere. Before and during World War II, U.S. isolationist tendencies meant regional interests were key, demanding that the United States' immediate surroundings be secure. In response to this impulse, the 4th fleet was established to ensure a naval presence in the Caribbean and the waters around Central and South America.

After World War II ended, the geopolitical scene shifted drastically. Priorities of security and military presence shifted quickly to the containment of communism and Soviet influence. In 1950, the U.S. disbanded the 4th Fleet, adding its responsibility (as well as the entire North Atlantic) to the 2nd Fleet; an obvious sign that priorities had shifted toward regions deemed more significant. Because there was minimal competition for hegemony and military dominance from Latin America, military assets were diverted elsewhere.

But in an April 24, 2008, Defense Department statement, U.S. Navy Adm. Gary Roughhead announced the re-establishment of the 4th Fleet. Although the announcement does not point to an increase in the number of surface combatants based at Mayport Naval Station in Jacksonville, Fla., for now there will be an increase in staffing for the region. The announcement also suggests the naval base will be a stronger candidate as the homeport of a nuclear-powered aircraft carrier, something many have lobbied for. Mayport was the home port for the USS John F. Kennedy, an older conventionally powered aircraft carrier. But the Kennedy was decommissioned in 2007, leaving the Florida naval base without a permanent aircraft carrier.

In the more than half a century since the disbanding of the 4th fleet, a few key geopolitical issues have shifted in the fleet's area of responsibility. The United States still enjoys a completely hegemonic military, dominating all the world’s oceans. Since the end of the Cold War, however, an increasing number of countries have expanded their naval influence to include more and more of the open ocean, a large improvement from the meek brown-water navies of previous decades.

Specifically, Brazil has been continuing its pursuit of power and influence, attempting to expand its naval might in the region. With a renewed presence in the region, the United States is effectively showing its desire to engage Brazil on its own terms early in the game to continue cooperation and prevent competition. The re-establishment of the 4th Fleet thus can be seen as a direct shift of focus to deal with increasing military activity in the region and to maintain maritime security in a developing Western Hemisphere.

Another regional shift important to the re-establishment of the U.S. 4th fleet is the development of international business, specifically in the energy sector. The recent announcement of a possible oil field discovery in Brazilian waters also suggest the region's increasing weight. With regional and global shipping traffic exploding in the years to come, the U.S. military is preparing to gradually add to the security of the region as it becomes more and more geopolitically significant.

Re-establishing the 4th fleet may not be felt as a drastic increase in physical presence in the short-term. The USS George Washington is participating in exercises with 12 South American navies off the coast of Brazil, for example. But Washington's renewed focus on the waters south of its borders can be seen as an important shift in the U.S. military stance toward its home hemisphere -- representing an adaptation to a quickly shifting geopolitical scene.