I believe Gerald Ford was President when the funds were cut off. Ford was a weakened President because he wasn't elected, and took over after a scandal, then pardoned Nixon, thus creating a terrible firestorm. He was also a creature of the Congress, having spent many many years there. I can't see him even considering trying to fund the war in Vietnam after just about everybody else was voting to cut and run. And this WAS what the American people wanted, apparently, after all the deaths and no end or victory in sight.