Why is breakup used here? Were Democratic Party and Republican Party one at that time?
"Yes, a long time ago. In 1824, the breakup of the Democratic-Republican Party resulted in four different candidates running for president and receiving electoral votes. Andrew Jackson was the top vote-getter, with 99 electoral votes -- 32 shy of a majority -- but the House chose John Quincy Adams as president. Something similar happened following the race for vice president in 1836. The U.S. Senate decided that contest, choosing Richard M. Johnson." SOURCE: http://www.bloomberg.com/politics/articles/2016-11-03/what-happens-if-nobody-wins-the-presidency-quicktake-q-a