be required to sever any ties they had with political parties and decided that it was unnecessary as it was "far better to leave ... conventions and practice to evolve". In 2007, Law Minister S. Jayakumar declared that the Government "made it a practice to always seek the President's views whenever it intends to move Constitutional amendments that affect the relevant provisions" concerning his discretionary powers. It has also been said that by convention it is a well-accepted practice that the President engages in charitable and community welfare work without government objection. Public international law As Singapore adopts a dualist rather than a monist view of law, public international law rules are not part of domestic law and cannot be enforced by the courts unless they have first been incorporated into domestic law in some way. Customary international law is defined in the Statute of the International Court of Justice as "evidence of a general practice accepted as law". Rules of customary international law can be declared by courts to be part of domestic law under certain conditions. However, they are not a source of constitutional law, because the Court of Appeal held in Yong Vui Kong that such rules can only be declared as part of the common law and cannot be directly incorporated into the Constitution. Unless an international treaty entered into by the Singapore Government has been given effect through an Act of Parliament, it cannot be enforced as domestic law by the courts. Nonetheless, such international obligations exert an influence on constitutional interpretation as the Court of Appeal has held that "the Singapore Constitution[ ] should, as far as possible, be interpreted consistently with Singapore's international legal obligations". However, it would not be appropriate for courts to refer to an international human rights norm if it does not accord with the way the constitutional text is worded, or if the history of the Constitution shows there was an intention to specifically exclude such a norm. Supremacy of the Constitution According to British jurist and constitutional theorist Albert Venn Dicey, three legal criteria must be satisfied before a constitution can claim to be supreme: There must be codification, that is, the constitution must be written. The constitution must be rigid. Authority must be given to the courts to evaluate the constitutionality of legislative acts and declare them void if they are found to be inconsistent with the