Which of the following political parties based its entire platform on the
issue of immigration?
(A) Whigs
(B) Democrats
(C) Free-Soilers
(D) Know-Nothings
(E) Republicans
It was primarily the "(D) Know-Nothings" that based its entire platform on the issue of immigration, since they felt that an influx of immigration--especially by Catholics--was detrimental to US society.