William H. Seward
The Republican Party had been founded in 1854, in reaction to the Kansas-Nebraska Act. Its anti-slavery stance was attractive to Seward, but he needed the Whig structure in New York to get re-elected. In September 1855, the New York Whig and Republican parties held simultaneous conventions that quickly merged into one. Seward was the most prominent figure to join the new party, and was spoken of as a possible presidential candidate in 1856. Weed, however, did not feel that the new party was strong enough on a national level to secure the presidency, and advised Seward to wait until 1860. When Seward's name was mentioned at the 1856 Republican National Convention, a huge ovation broke out. In the 1856 presidential election, the Democratic candidate, former Pennsylvania senator James Buchanan, defeated the Republican, former California senator John C. Frémont, and the Know Nothing candidate, former president Fillmore.
History of immigration to the United States
Irish and German Catholic immigration was opposed in the 1850s by the Nativist/Know Nothing movement, originating in New York in 1843 as the American Republican Party (not to be confused with the modern Republican Party). It was empowered by popular fears that the country was being overwhelmed by Catholic immigrants, who were often regarded as hostile to American values and controlled by the Pope in Rome. Active mainly from 1854–56, it strove to curb immigration and naturalization, though its efforts met with little success. There were few prominent leaders, and the largely middle-class and Protestant membership fragmented over the issue of slavery, most often joining the Republican Party by the time of the 1860 presidential election.