Meanwhile the followers of Madero and the pronounced Radicals had found a new northern leader in the person of Venustiano Carranza. They called themselves Constitutionalists, as indicative of their purpose to reestablish the constitution and to choose a successor to Madero in a constitutional manner. What they really desired was those radical changes along social, industrial, and political lines, which Madero had championed in theory. They sought to introduce a species of socialistic regime that would provide the Mexicans with an opportunity for self-regeneration. While Diaz had believed in economic progress supported by the great landed proprietors, the moral influence of the Church, and the application of foreign capital, the Constitutionalists, personified in Carranza, were convinced that these agencies, if left free and undisturbed to work their will, would ruin Mexico. Though not exactly antiforeign in their attitude, they wished to curb the power of the foreigner; they would accept his aid whenever desirable for the economic development of the country, but they would not submit to his virtual control of public affairs. In any case they would tolerate no interference by the United States. Compromise with the Huerta regime, therefore, was impossible. Huerta, the "strong man" of the Diaz type, must go. On this point, at least, the Constitutionalists were in thorough agreement with the United States. A variety of international complications ensued. Both Huertistas and Carranzistas perpetrated outrages on foreigners, which evoked sharp protests and threats from the United States and European powers. While careful not to recognize his opponents officially, the American Government resorted to all kinds of means to oust the dictator. An embargo was laid on the export of arms and munitions; all efforts to procure financial help from abroad were balked. The power of Huerta was waning perceptibly and that of the Constitutionalists was increasing when an incident that occurred in April, 1914, at Tampico brought matters to a climax. A number of American sailors who had gone ashore to obtain supplies were arrested and temporarily detained. The United States demanded that the American flag be saluted as reparation for the insult. Upon the refusal of Huerta to comply, the United States sent a naval expedition to occupy Vera Cruz.