Which of the following was not a third-party challenger?

Whig Party

Progressive Party

Dixiecrats

Green Party

The Whig Party was not a third-party challenger.

Explanation:

The Whig Party was an American political party founded by politician and lawyer Henry Clay during the era of "Jacksonian democracy." Founded between 1833 and 1834, the party formed in opposition to the policies of President Andrew Jackson and the Democratic Party. The party dissolved in 1856, its components were mostly absorbed by the Republican Party, but some factions still acted until 1860.

The political ideology of the party was based on protectionism and modernization. The party received this denomination in analogy to the British Whigs, who opposed royal power during the English Restoration.