When is a bilateral treaty that only one party has ratified binding? Apparently whenever it involves the the U.S.-U.K. "special relationship." In reality, it's not that simple, but Tony Blair's critics are justifiably angry over what appear to be some unilateral obligations that have been imposed by a post-9/11 bilateral extradition treaty with the United States.
The current controversy involves the NatWest Three--three British bankers who were put on a plane this morning to Houston, Texas to face charges related to the collapse of Enron. Extradition of the three is occurring pursuant to a U.S.-U.K. extradition treaty negotiated in the aftermath of the 9/11 attacks. Although the treaty's terms are very favorable to American interests (allowing, for example, different evidentiary standards for the United States and the United Kingdom to gain extradition), the United States has not yet ratified the agreement.
Why did the British feel compelled to extradite suspects to the United States in the absence of American ratification of the extradition treaty? I welcome amendments or corrections from readers who know more about this situation than I do, but it appears that the British government is acting under a statutory (i.e., domestic law) obligation adopted in anticipation of the treaty's entry into force. Unlike the United States, the United Kingdom treats all international agreements as non-self-executing. In other words, implementing legislation must always be enacted in order to give effect to treaties within the British legal system. (In the United States, whether a treaty is self-executing--and therefore a direct source of justiciable rights and obligations--or non-self-executing depends on the wording of the treaty itself.)
Ordinarily, the required implementing legislation would be enacted by the British government pursuant to (or perhaps subject to) the entry into force of the treaty. In this case, perhaps due to Blair's interest in ingratiating himself with President Bush, the House of Commons adopted implementing legislation without waiting for U.S. Senate action on the treaty. Now, as a consequence, the U.K. bears all of the obligations of the treaty while the United States bears none of them.
Needless to say, this situation has made many Britons unhappy with both the British and the American governments. The Guardian reports that "the government is sending Baroness Scotland, the Home Office Minister in the House of Lords, to Washington to deliver the message that Senate ratification of the treaty is now essential." Somehow I rather doubt that the United States Senate will feel the same sense of urgency regarding this matter that the Blair government feels.