King George wants a line item veto?
There was a line item veto once before. It was put in place in the early 90s, and was then overtuned by the U.S. Supreme Court in a case titled Clinton v. City of New York on June 25, 1998.
The Supremes found this law violated the 'presentment clause' of the Constitution. The presentment clause can be found in Article I Section 7 of the Constitution, which reads in part, "Every bill which shall have passed the House of Representatives and the Senate, shall, before it become a Law, be presented to the President of the United States; If he approves he shall sign it, but if not he shall return it, with his Objections, to that House in which it shall have originated, who shall enter the Objections at large on their Journal, and proceed to reconsider it."
In other words, the Constitution directly requires an all or nothing approval by the president. No part approval or part veto. To change this, an amendment to the constitution will be required.
Aside from the crazy idea that anyone would give King George even more power, his request of Congress has already been found unconstititional by the Supreme Court. His request for a line item veto is nothing more than empty political rhetoric.