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.
American Republican Party (1843)
The American Republican Party was a minor nativist political organization that was launched in New York in June 1843, largely as a protest against immigrant voters and officeholders. In 1844, it carried municipal elections in New York City and Philadelphia and expanded so rapidly that by July 1845 a national convention was called. This convention changed the name to the Native American Party and drafted a legislative program calling for a twenty-one-year period preceding naturalization and other sweeping reforms in the immigration policy. Failure to force congressional action on these proposals, combined with the growing national interest in the Mexican problem before the Mexican–American War, led to the party's rapid decline.