There was more danger in carrying forward the program which was intended to secure to the United States Oregon, California, and New Mexico. But the first step had already been taken. In April, 1846, both House and Senate, in spite of the opposition of the older leaders, authorized the President to give notice to England that joint occupation should cease at the expiration of a year. The English people were much excited, and the idea prevailed that this was only a move on the part of the United States to seize Canada, but the British Government renewed the proposition to compromise on the forty-ninth parallel, Vancouver Island to remain in British possession. A treaty to this effect was accepted by both Governments during the summer of 1846. Polk could boast that the Oregon question had been settled. Again the Northwestern Democrats, who had been promised all of Oregon, were sorely disappointed. One of their most popular leaders declared in the Senate: "James K. Polk has spoken words of falsehood, and with the tongue of a serpent." Would the Northwestern wing of the party continue loyal? This may, perhaps, best be answered when we come to discuss the Wilmot Proviso. When the Oregon question was at its acutest stage, in the autumn of 1845, Polk sent John Slidell, an adroit politician of Louisiana, to Mexico, to renew the friendly relations which had been broken off immediately after the passage of the joint resolution by Congress. Slidell was authorized to negotiate a treaty by which European influence, then being exerted in Mexico against the United States, was to be counteracted, the annexation of Texas approved, and all of the claims of American citizens against Mexico were to be definitely satisfied. But as Mexico had no funds in her treasury, Slidell was to assume for the United States all these obligations, and pay the Mexicans $5,000,000 in return for the cession of New Mexico, a part of which was claimed by Texas. Finally Slidell was to purchase California, if that were found to be possible, and raise the cash payment from $5,000,000 to $25,000,000. Slidell's mission was supported by a naval demonstration in Mexican waters, and the meaning of his presence was made very plain to the people of the distressed republic.