THE younger George Bush, a Republican, negotiated the Convention on the Rights of Persons with Disabilities. But when it came before the American Senate last year 38 Republicans blocked it. Now the treaty is up for consideration again; its prospects are uncertain. If it passes, it will only be with “reservations”: clauses that qualify how the treaty will impinge on American law. Like other human-rights treaties that America has ratified, it will be “non-self-executing”, meaning that separate laws are needed to give it effect. Conservative waverers may demand more sops, such as protection for parents who teach their disabled children at home.

America is not the only country that says “Yes, but” to treaties. A third of the countries that ratified UN conventions on the rights of women, children and racial minorities carved out areas where the treaties would not apply, according to a study by Beth Simmons, a scholar of international affairs at Harvard University. In 2002 more than half the 147 adopters of the International Covenant on Civil and Political Rights had caveats. The UN considers 36 treaties to be “close to universal” (meaning that more than 80% of countries have ratified them); in more than half the cases some ratifiers reserve the right not to apply them in full.

In theory, reservations are allowed only if they are compatible with the treaty’s objective. Often they are not. Saudi Arabia supposedly pledged to end “all forms of discrimination against women”, but whittled that down to merely some forms. It was one of several Muslim nations that joined the treaty saying that anything that contradicted sharia law would not apply. The freedom of Saudi women to travel, open a bank account and choose a husband is thus still curtailed.

There is a case for à la carte accession to human-rights treaties. Merely signing up to one puts those rights up for discussion and raises expectations, says Ms Simmons. As domestic laws and social norms evolve, some countries then drop their reservations. Kuwait, for example, adopted the women’s-rights convention in 1994 without letting women vote or run for office. In 2005 the emirate gave them full political rights. America ratified the political-rights convention in 1992 with the stipulation that people under 18 could still be executed. The Supreme Court has since ruled that such executions are unconstitutional.