Fear of being seen week; Nixon didn't want to be the first President to loose a war on America's behalf, thus was drawn in to the so called quagmire theory.
Incompetence of the ARVN; The ARVN weren't trained properly, at first the USA disguised their entry to Vietnam againt the Genevea accords as their reason for being there being they were training the ARVN, but when the time came for Vietnemisation, they did'nt live up to the standard. Thus Nixon couldn't leave immediatly as he wanted. or else America's whole reason for going to Vietnam in the first place would have been for nothing, as a communist attack would come soon enough and the ARVN would be defenseless.
Bombing offensives didn't bring North Vietnam to the negotiation table as planned; Nixon had hoped that by using bombing offenses such as Rolling Thunder he could have bought NV to the negotiation table sooner, nonetheless he failed at this. NV held out for what they wanted until Nixon came to an agreement some time later.
Nixon rejected peace terms of 72, then agreed same terms in 73; during election hyear Nixon…