The year 2013 has marked the decline of American power and leadership. This has become more and more clear to the rest of the world, mainly because of the constant problems plaguing internal U.S. politics and the lack of leadership abroad, particularly the "neo-isolationism" in foreign affairs and a serious weakening of the current government's unity.

As Fareed Zakaria wrote in 2008, the "rise of other powers" in the international arena was inevitable thanks to America's carelessness. Many nations have now grown to become regional or midsized powers — as stated in Martin Holbraad's theory of 1980 — called upon to maintain stability in their closest areas of influence, allowing them to be viewed as nations that support a favorable status quo, which, in turn, gives them more weight in global affairs.

And two nations — China and now Russia — have clearly risen above the rest to challenge the power of the U.S. on the front lines with what Joseph Nye in 1990 called "hard power." Now, these countries have the power to affect geopolitical and strategic struggles in volatile areas like the Middle East.

Internal weakness: The recent paralysis of public administration as a result of the power struggles between Republicans and Democrats — the U.S. essentially could not pay its own bills — generated a global uncertainty about the U.S. because of the negative effect this might have had on markets.

The lack of any mutual support between Republicans and Democrats has left the Obama administration weak and unable to negotiate the programs and policies it wants, casting only more doubt over its power internationally.

External weakness: With its recent inability to deal effectively with the chemical weapons crisis in the Syria, the U.S. has proven itself less powerful abroad, unable to count on the support of its "traditional allies" for another military resolution.

Russia took great advantage of the situation by proposing a plan to destroy Syria's chemical weapons, receiving support from the rest of the world and discouraging those countries hungry for more war.

There is no doubt the U.S. is still a world power; however, as time passes, that power is diminishing and giving way to a certain multilateralism, with China and Russia in tight competition for the world's most powerful nation.