How did the Vietnam war take its course?

The Vietnam War escalated from a small amount of military personnel, a small amount of river patrol boats, a small amount of attack aircraft, a small amount of artillery, and small unit engagements. As the years rolled by, more men were thrown into the fight, more tanks landed ashore, more patrol boats were put into service, more bombers filled the skys. Battles got bigger, and bloodier. It all reached it's zenith during TET offensive of '68, when the US realized that "...they're not defeated at all!" Prior to TET, we believed that we "had em on the run." But apparently that was not the case. From that point on, the course in Vietnam reversed, we prepared for de-escalation, commencing in 1969.