The Know-Nothing Party, or the American Party, (OHC) was founded in New York in 1849 (Billington) in opposition to immigrants and especially the Catholic Church. (OHC) They expanded fast enough to become a national organization between 1852 and 1854. (Billington)

They thought that Catholics were under the total control of the Pope in Rome, and that they would be loyal to him, not the U.S. Some of the Know-Nothings feared that Catholics planned to take over the U.S. (OHC) They especially despised the Irish immigrants, who were Catholic. (MNAA)

The Know-Nothings goal was to prevent immigrants and Catholics from gaining political positions or "jobs in the private sector", because they wanted the economy to be run by "true Americans", and they feared job competition, since they were mostly (OHC) "native-born, white, Anglo-Saxon" (MNAA) middle or working class men. (OHC) All members of the party "were pledged to vote only for native Americans". (Billington)

The party was very secretive, and members would not reveal any information to any non-member, replying to any question with "I know nothing," hence the name. (OHC)

They were successful during the 1850's because of the peaking of anti-Catholic sentiment in America. (Billington) One victory for the Know-Nothings was when their candidates won control of the Massachusetts legislature in 1854. Another was in 1855 when support from Know-Nothings in Ohio helped Salmon Chase win the spot as governor. (OHC) They also did very well with their nativist mindset in Pennsylvania and New York. (Brinkley)

However, one of their greatest losses was when their presidential candidate, Millard Fillmore, lost to both the Republican and Democrat candidates in 1856. (OHC)

When slavery became a more pressing issue than immigrants and Catholics and the Know-Nothings refused to have an opinion about it, they were declined in the 1860 election, and the party dissolved, many choosing to join the Republicans. (OHC) By 1859, the Know-Nothings had no influence on the national scale, and would quickly die out completely. (MNAA)

I think that the Know-Nothings were overall a failure as a party, because they failed to last as a party or make much of a lasting impact on the national government, especially in the things they were fighting against.