Why did the vietnamese tet offensive marked a dramatic turning point in the war?

This was the origin of the tet offensive. a campaign of a breath taking breadth, speed and scope. it shook us imperialisms to its roots and had a dramatic lasting effect on us public opinion. He carefully planned the offensive , utilising the techniques he had learned in the struggle with the french, where he had learned how to approach the enemy's stregth.

C maybe i might be wrong