Since World War II the United States has been the undisputed world-leading superpower. This will not always be the case. Bible prophecy shows that a different superpower will exist immediately before Jesus Christ's return. It will be a great religious and commercial system whose trade, culture and strong military dominates the world.
British historian Paul Kennedy, who now lectures at Yale, wrote his monumental book The Rise and Fall of the Great Powers in 1987. In it, looking back to the year 1500, he showed that the qualities that lead to nations' rising to power and the reasons for their decline and fall have certain commonalities: debt and imperial overreach.
Just as the British Empire collapsed due to debt and an overstretched military, so the United States faces the same problems today. It stretches to field enough troops for all its military commitments. Astronomical debt is a crucial and growing problem.
Only a generation ago the United States was in such sound financial condition that it was the world's greatest lender. That's no longer the case. Due to its overspending, it's now one of the most indebted nations in history.
There's another reason we can know the United States won't be that dominant superpower leading the world before Christ's return: There are too many details given in Bible prophecy about the beast power that just don't fit with the description of the United States.
Primarily, the description of the beast in Daniel 7:7 says that the beast was "dreadful and terrible, exceedingly strong. It had huge iron teeth; it was devouring, breaking in pieces, and trampling the residue with its feet." This beast was represented by iron legs in the dream of Nebuchadnezzar and as a beast with iron teeth in Daniel 7. The historic Roman Empire fits this description in that it ruthlessly crushed its enemies and ruled with an iron fist.
In contrast, the United States as a superpower on the world stage has never wielded power in the same way other superpowers before it have. Consider the aftermath of World War II. Instead of annihilating its former enemies Germany and Japan in a declaration of victory, the United States enacted policies and spent considerable money to help those nations rebuild after defeating them. Not that the U.S. has always had pure motives or done the right thing in every case (its dealings with the native American people, or the U.S. government's complicity in the legalization and commercialization of abortion and pornography, for example). But as a self-proclaimed beacon of freedom in a world where communism and dictatorship threatened billions around the globe, the U.S. has acted in many cases out of a motivation to do good for the people of any given country.