He soon became one of the recognized leaders of the Whig party in his state, and “no small share of the flashes of success that came to it in the last decade of its existence in Louisiana is attributable to his energy and political sagacity.” He was, according to the journalistic custom of that time, savagely assailed by the newspapers which opposed him, and he was even charged, in 1844, with belonging to the “Know Nothing” party, despite the fact that he was himself foreign born. But he agreed with that party in his opposition to the granting of suffrage to immigrants into the state, even to natives of Northern States, in whom he saw a source of danger to the South. His seat in the Constitutional Convention of 1844 being contested, he resigned and was re-elected by a much larger majority. When he again took his seat at the convention which re-assembled in New Orleans, Benjamin was the recognized leader of the delegates of that city in its disputes with the representatives of the country districts. One of his speeches at that convention proved that he clearly foresaw the war in 1845, though he was then considered an alarmist. He was elected a State Senator in 1852, and soon became a leading candidate for the United States Senate. He received the nomination by an unexpectedly large majority and was elected in the same year, as a Whig. When that party was split by the antagonism between the North and the South, he came out openly in 1855 with the declaration that it did not exist any more as a national party. He urged the necessity of uniting in one great Southern party, on a platform “on which we can all stand together to meet with firmness the coming shock.” When the formation of such a party proved impracticable, he turned to the Democratic party and became more friendly to the administration. His first really powerful speech in the Senate was delivered May 2d, 1856, on the Kansas bill, in which he distinctly and calmly enunciated the right of secession. In 1859 Benjamin was re-elected to the United States Senate by a majority of one vote (that of the last “Know Nothing” in the Louisiana Legislature). He was now one of the prominent Senators, and chairman of the Judiciary Committee. He was in favor of secession only as a last resort; but he thought that this last resort was reached after Lincoln’s election in 1860. He delivered two powerful orations in the Senate in the following winter, and a memorable farewell speech, February 4, 1861, on the right of Louisiana to secede. His last speech in the capital was delivered before the Washington Artillery on Washington’s birthday, and soon after, in New Orleans, he took leave from his family, whom he was never to see again.