In support: The president has a constitutional right and political duty to play a integral role in the legislative process. Article II, Section 3 of the Constitution requires that the president "shall from time to time . . . recommend to [Congress'] Consideration such Measures as he shall judge necessary and expedient." Further, Article I, Section 7 requires that to become and actual law, a bill requires the president's signature. "If he [the president] approve it he shall sign it, but if not he shall return it, with his Objections to that House in which it shall have originated."
In his widely acclaimed "The American Presidency," 110 (2d ed. 1960), author Clinton Rossiter, suggests that over time, the president has become "a sort of prime minister or 'third House of Congress.' . . . [H]e is now expected to make detailed recommendations in the form of messages and proposed bills, to watch them closely in their tortuous progress on the floor and in committee in each house, and to use every honorable means within his power to persuade . . . Congress to give him what he wanted in the first place."
Thus, suggests the Justice Department, it may be appropriate for the president, through signing statements, to explain what his (and Congress') intention was in making the law and how it will be implemented, particularly if the administration had originated the legislation or played a significant part in moving it through Congress.
On the other hand: The argument against a president using signing statements to alter Congress' intent as to meaning and enforcement of new laws is once again based in the constitution. Article I, Section 1 clearly states, "All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives." Not in a Senate and House and a president. Along the long road of committee consideration, floor debate, roll call votes, conference committees, more debate and more votes, the Congress alone creates the legislative history of a bill. It can also be argued that by attempting to reinterpret or even nullify parts of a bill which he has signed, the president is exercising a type of line-item veto, a power not currently bestowed on presidents.
The recent use of presidential signing statements to functionally amend legislation passed by Congress remains controversial and is arguably not within the scope of powers granted to the president by the Constitution. The other less controversial uses of signing statements are legitimate, can be defended under the Constitution and can be useful in the long-term administration of our laws. Like any other power, however, the power of presidential signing statements can be abused.