Arbitration clauses may potentially be challenged as unconscionable and, therefore, unenforceable. This did not however result in those orders being ruled unenforceable or unconstitutional. The law makes surrogacy agreements unenforceable. The term is frequently used in contradistinction to the term "voidable" and "unenforceable". This has not been implemented until now as Directive Principles are Constitutionally unenforceable. RE 37,516 has been declared invalid and unenforceable. Teva had argued that the Pfizer patent was invalid and unenforceable. Mr El Makdessi argued that they were unenforceable penalty clauses. McManaman argued that his contract was unenforceable and an unlawful restraint of trade. The United States Supreme Court declared restrictive covenants unenforceable in 1948 in Shelley v. Kraemer. This may render a contract void or unenforceable. A way it can be done is by deeming the contract unenforceable. California repealed the unenforceable sections of Proposition 187 in 2014. The trial judge declared the ordinance's requirement that Ypsilanti prosecute only under city law unenforceable. Alberta repealed prohibition in 1924, along with Saskatchewan, upon realizing that the laws were unenforceable.