The Republican party was America’s first political party that had as it’s goal the creation of an activist federal government dedicated to social reform.
In mid-1861, with the War for Southern Independence just beginning, US Treasury Secretary Salmon Chase asked for and received from Congress the first income tax instituted in America. It began as a 3% federal tax on all income, but was raised to 5%. It was a graduated income tax, just as proposed by Marx just 13 years earlier.
(2nd plank of the Communist Manifesto)
As the war progressed, Lincoln desperately needed money. In 1862, he issued $450 million in fiat currency. This paper money was legalized by an act of Congress with nothing to secure it.
(5th plank of the Communist Manifesto)
After the failed socialist revolutions of 1848 which encompassed most of the European continent, many German, English, Hungarian, Bavarian, etc. socialists flocked to the United States having been banned from their homelands for treason. Just about all of them wound up in the North as ardent supporters of the Republican party.