The problem which perhaps affected the United States most during the 25 year period cited was the war in the Gulf which showed that the US remained a belligerent nation and did not actually learn the lesson of the Vietnam War, a decision which perhaps would come back to haunt the nation in the future and which was certainly realized in the September 2001 attacks. The fact that the US entered Kuwait and affronted Iraqi dictator Sadam Hussein with full military might but did not close off the job by deposing the dictator was perhaps the biggest mistake in their foreign policy which ended up haunting them in the long run (Bush, 1990).
Adding to that, the US intervention in Kuwait brought about an increased tendency to Arab militantism which was ultimately much more damaging to the American and Western psyche and which led to a huge rise in terrorist incidents across the world, largely aimed at the United States. This caused a deteriorating relationship with Israel too especially where democratic Presidents were concerned and obviously this all came about due to what could be termed as a two pronged attack on the American way of life (Bowles, 2011).
Thus the impact on the United States was substantial and rather great in that sense and what could be worse than the September 2001 attacks? All this was the eventual result of American belligerence in the Arab world where an iron fisted approach and meddling interventionism resulted in a situation where the American nation had to lose thousands of lives in the largest and most destructive terrorist act in history. This definitely contributed to America becoming a restless giant.
References:
Bowles, M. (2011). A history of the United States since 1865. San Diego, CA: Bridgepoint Education.
Letter from President George H.W. Bush to his children on New Year’s Eve 1990 regarding his concerns about war with Iraq (1990)
Letter from Ronald Reagan to Mikhail Gorbachev desiring a better relationship between the nations (1985)