Why did the National Republican Parties split into the Democratic-Republican Party?

Answer 1

The question is backward: Jefferson's Democratic-Republican party split into the National Republican Party and the Democratic Party after the Presidential election of 1824.

Once the Federalist Party collapsed, the Democratic-Republican party dominated government, but there was a false sense of non-partisanship. The party split into separate factions because some members held onto traditional Democratic-Republican ideology, such as supporting states' rights, while others' beliefs were more in line with the defunct Federalist party. The differences came to a head during the 1824 Presidential election when the party members battled over which candidate to back. As a result, four men ran for President in the 1824 election: John Quincy Adams, Andrew Jackson, William H. Crawford and Henry Clay.

None of the candidates received enough electoral votes to win outright, so the decision was sent to the US House of Representatives. Speaker of the House, Henry Clay detested Andrew Jackson, so he dropped out of the race and gave his support to John Quincy Adams, whose views were closer to his own. Adams received the majority of House votes on the first ballot cast, and was named President. Adams, in turn, named Henry Clay his Secretary of State.

Jackson, and many of his supporters believed Clay had made a "corrupt bargain," thus creating in-fighting within the Democratic-Republican Party. The differences between the two factions became so obvious that they split into new parties, the National Republicans (John Quincy Adams) and the Democrats (Andrew Johnson).

Jackson campaigned against Adams in 1828 by accusing him of corruption, and subsequently defeated Adams for the Presidency.

Answer 2

The Jeffersonian Democratic-Republican Party split into the National Republican Party and the Democratic Party around 1824.