The Congressional Research Service has issued an important report that is highly critical of Bush's attempt to expand Executive power via signing statements. The report concludes that these statements don't have any legal force and are therefore insignificant in terms of Constitionality:
Presidential signing statements have a long historical pedigree and there is no discernible constitutional or legal impediment to their issuance. While such statements have become increasingly common since the Reagan Administration and have increasingly been utilized by Presidents to raise constitutional or interpretive objections to congressional enactments, that increased usage does not render them unconstitutional. While the broad assertions of executive authority contained in these statements carry significant implications, both practical and constitutional, for the traditional relationship between the Executive Branch and Congress, they do not have legal force or effect, and have not been utilized to effect the formal nullification of
The report goes on to say that the statements are problematic in their intent--as a means of asserting broad Executive authority that the president does not have ex cathedra:
Instead, it appears that recent administrations, as made apparent by the voluminous challenges lodged by President George W. Bush, have employed these instruments in an attempt to leverage power and control away from Congress by establishing these broad assertions of authority as a constitutional norm. It can be argued that the appropriate focus of congressional concern should center not on the issuance of signing statements themselves, but on the broad assertions of presidential authority forwarded by Presidents and the substantive actions taken to establish that authority. Accordingly, a robust oversight regime focusing on substantive executive action, as opposed to the vague and generalized assertions of authority typical of
signing statements, might allow Congress in turn to more effectively assert its constitutional prerogatives and ensure compliance with its enactments.