Morton was originally a Democrat and opposed to the extension of slavery , but he became one of the organizers of the Republican Party . In 1856 , after he joined the Republicans , he was one of three delegates from Indiana that attended that party 's organizational convention in Pittsburgh . In 1856 he was nominated by his new party for the position of governor of Indiana . In 1860 he was elected lieutenant governor on the ticket with Henry S. Lane . He became governor when Lane was elected to the United States Senate . Morton was re-elected in 1864 and served until 1867 , in which time he was elected to the United States Senate . He was re-elected in 1873 to the Senate . As Senator he worked for the adoption of the Fifteenth Amendment , was involved in the impeachment of Andrew Johnson , and was a trusted advisor of the Republicans in the South . At the national Republican convention in 1876 he received the second-highest number of votes for the presidential nomination . He was considered a leading Radical Republican during his government career . He died on November 1 , 1877
national Republican convention in 1876
1876 Republican National Convention
Oliver P. Morton (monument)