The Line Item Veto Act is unconstitutional because it allows the president to amend or repeal parts of statutes without the pre-approval of Congress. According to the Presentment Clause of the Constitution, Congress must initiate all changes to existing laws. Decided June 25, 1998 (argued April 27, 1998). Opinion of the Court: John Paul Stevens → go there Dissenting: Breyer. Topic: Separation of powers. Clinton v. City of New York, 524 U.S. 417 (1998), is a landmark decision by the Supreme Court of the United States in which the Court held, 6–3, that the line-item veto, as implemented in the Line Item Veto Act of 1996, violated the Presentment Clause of the United States Constitution because it impermissibly gave the president of the United States the power to unilaterally amend or repeal parts of statutes that had been duly passed by the United States Congress. Justice John Paul Stevens wrote for the six-justice majority that the line-item veto gave the president power over legislation unintended by the Constitution, and was therefore a violation of the separation of powers between the two branches. Wiki link