Enraged at this favor shown to his rival, Villa determined deliberately to provoke American intervention by a murderous raid on a town in New Mexico in March, 1916. When the United States dispatched an expedition to avenge the outrage, Carranza protested energetically against its violation of Mexican territory and demanded its withdrawal. Several clashes, in fact, occurred between American soldiers and Carranzistas. Neither the expedition itself, however, nor diplomatic efforts to find some method of cooperation which would prevent constant trouble along the frontier served any useful purpose, since Villa apparently could not be captured and Carranza refused to yield to diplomatic persuasion. Carranza then proposed that a joint commission be appointed to settle these vexed questions. Even this device proved wholly unsatisfactory. The Mexicans would not concede the right of the United States to send an armed expedition into their country at any time, and the Americans refused to accept limitations on the kind of troops that they might employ or on the zone of their operations. In January, 1917, the joint commission was dissolved and the American soldiers were withdrawn. Again the "first chief" had won! On the 5th of February a convention assembled at Queretaro promulgated a constitution embodying substantially all of the radical program that Carranza had anticipated in his decrees. Besides providing for an elaborate improvement in the condition of the laboring classes and for such a division of great estates as might satisfy their particular needs, the new constitution imposed drastic restrictions upon foreigners and religious bodies. Under its terms, foreigners could not acquire industrial concessions unless they waived their treaty rights and consented to regard themselves for the purpose as Mexican citizens. In all such cases preference was to be shown Mexicans over foreigners. Ecclesiastical corporations were forbidden to own real property. No primary school and no charitable institution could be conducted by any religious mission or denomination, and religious publications must refrain from commenting on public affairs. The presidential term was reduced from six years to four; reelection was prohibited; and the office of Vice President was abolished. When, on the 1st of May, Venustiano Carranza was chosen President, Mexico had its first constitutional executive in four years. After a cruel and obstinately intolerant struggle that had occasioned indescribable suffering from disease and starvation, as well as the usual slaughter and destruction incident to war, the country began to enjoy once more a measure of peace. Financial exhaustion, however, had to be overcome before recuperation was possible. Industrial progress had become almost paralyzed; vast quantities of depreciated paper money had to be withdrawn from circulation; and an enormous array of claims for the loss of foreign life and property had rolled up.