Is it actually unconstitutional? or was the supreme court at the time politically biased? I always thought it would be a good way to get rid of the Pork/Payoffs the Traitors/CONgress inserted into the budget.
Yes, it is. Congress writes legislation, that is clearly stated in Article I. The President either signs what they send him or he vetoes what they send him, Article I again. Nothing in the Constitution, expressed or implied, allows the president to write his own legislation by picking and choosing parts of what Congress passed.