Finally, Constitutional or Supreme Courts may play a role in the procedure of constitutional amendment, including of presidential terms. Indeed, constitutional review may be required, or possible, either a priori or a posteriori, but the Venice Commission stresses that Constitutional Courts should intervene after the amending text has been adopted by the constitutional legislator pursuant to the relevant, special constitutional requirements. The Venice Commission has previously examined the different forms of involvement of the Constitutional Court in the amendment procedure: besides the unproblematic, widespread a posteriori review of whether the correct procedures for constitutional amendment have been respected, it has found that the mandatory a priori judicial review of proposals for constitutional amendment could bring excessive rigidity to the process and even have unintended political consequences. As regards the possibility for the Constitutional Court to carry out a substantive a posteriori review that the amendment adopted is not in breach of “unamendable” provisions or principles, the Venice Commission has expressed the view that it is a “problematic instrument, which should only be exercised in those countries where it already follows from clear and established doctrine, and even there with care, allowing a margin of appreciation for the constitutional legislator”. In the Commission’s view, “as long as the special requirements for amendment in the constitutions of Europe are respected and followed, then these are and should be a sufficient guarantee against abuse.”