In 1920, Sonoran general Alvaro Obregón was elected president of Mexico. A key task was to secure diplomatic recognition from the United States. The American-Mexican Claims Commission was established to deal with claims by Americans for property-loss during the Revolution. Obregón also negotiated the Bucareli Treaty with the United States, an important step in securing recognition. Concessions made to foreign oil during the Porfiriato were a particularly difficult matter in the post-Revolutionary period, but General and President Alvaro Obregón negotiated a settlement in 1923, the Bucareli Treaty, that guaranteed petroleum enterprises already built in Mexico. It also settled some claims between the U.S. and Mexico stemming from the Revolution. The treaty had an important impact for the Mexican government, since it paved the way for U.S. recognition of Obregón's government. The agreement not only normalized diplomatic relations, but also opened the way for U.S. military aid to the regime and gave Obregón the means to suppress a rebellion. As the Porfiriato had demonstrated, a strong government that could maintain order paved the way for other national benefits; however, the Constitution of 1917 sought to enshrine rights of groups that suffered under that authoritarian regime.