What 1968 event caused u.s. military leaders to be concerned that a quick end to the war was not possible?

Greek culture spread throughout the non-Greek world.

Explanation:

The Hellenistic period in history began with the conquests of Alexander the Great and was a time of military and political domination of the Greek Macedonians in the Mediterranean and the Middle and Middle East. The political dominance of Macedonians over other nations from Egypt and Syria all the way to India will be accompanied by Greek or Hellenic cultural influence. They would gradually make their place on the world stage before the Roman and conquests at the beginning of the 1st century BC.

The Hellenistic period is a time of connecting and pervading different cultures and religions of East and West, followed by the suppression of religious intolerance and national or tribal divisions. Numerous population migrations followed, the creation of new cities and states, and the gradual relocation of cultural centers from Greece and Mesopotamia to Syria and the eastern shores of the Mediterranean, especially in newly built or rebuilt cities.