The Office for Israeli Constitutional Law, a non-governmental legal action organization, sent a letter to US Secretary of State Hillary Clinton last week, warning that by labeling Jewish settlements in the West Bank illegal, she is violating international law. The little-known Anglo-American Convention, a treaty signed by the US and British governments in 1924, stipulated that the US fully accepted upon itself the Mandate for Palestine, which declared all of the West Bank within its borders. "The treaty has been hidden," said OFICL director Mark Kaplan. "But if you look at the House [of Representatives] deliberations during World War I, people are saying, 'Look, we've invested a lot of money in Palestine, and we expect that this treaty will be upheld.'" Though the United Nations' 1947 partition plan declared the West Bank an Arab territory, the mandate's borders still hold today. "The mandate expired in 1948 when Israel got its independence," Kaplan said. "But the American-Anglo convention was a treaty that was connected to the mandate. Treaties themselves have no statute of limitations, so their rights go on ad infinitum." "The UN partition plan was just that-a plan," said OFICL chairman Michael Snidecor in a statement. "The General Assembly has no authority to create countries or change borders." Clinton's rhetoric, according to Kaplan, has become more and more troubling. "Our letter was sent as a result of so many comments that have been made by the secretary of state," he said. "It's part of a process that we've been involved with for a number of months, but we're speeding things up because of the acceleration of recent events." A few days after praising Israel for its "unprecedented" actions in freezing settlement activity, Clinton reemphasized the supposedly illegal status of the settlements. "The United States believes that settlements are not legitimate," she said. "That has been the policy of our government for 40 years. That is the policy of President [Barack] Obama today and going forward." According to Kaplan, the IDF presence in the West Bank has added to this misconception of illegal activity. "Israel chose to adopt a policy of military rule in 1967, which makes it smell of occupation," Kaplan said. "And the world says it is illegal occupation because of all the propaganda that's been out there. Israel's presence in Judea and Samaria does not qualify as an occupation under international law because of the Anglo-American Convention, and if you look at the Hague and Geneva conventions." The OFICL letter also warned Clinton that if her office does not comply with the civil rights recognized in the Anglo-American convention, OFICL will file a class-action suit in a US district court. Prime Minister Binyamin Netanyahu declared a 10-month settlement freeze last Wednesday, but the letter, which was also sent to Netanyahu's office, states that under the legal principle of estoppel - which precludes someone from denying the truth of a fact which has been determined in an official proceeding or by an authoritative body - any demand on Israel to freeze construction within the mandated borders is illegal under US law. According to one adviser, Netanyahu's staff is reviewing the documents and will discuss the issues before replying to OFICL's planned actions.