Which Act led to the disintegration of the Whig Party?

 The Whigs collapsed following the passage of the Kansas–Nebraska Act in 1854, with most Northern Whigs eventually joining the anti-slavery Republican Party and most Southern Whigs joining the nativist American Party and later the Constitutional Union Party.

Explanation:

regarding the law, the 15th amendment was specifically designed thinking in the rights of black free men.

even though ratified on february 3, 1870, the promise of the 15th amendment would not be fully applied for a long time.poll taxes and literacy tests would allow southern states disenfranchise african americans. only in 1965 the voting rights for african americans would be actually able to vote in the south.

in 1965, president johnson signed the voting rights act, which aimed to overcome legal barriers that prevented african americans from voting as it was guaranteed by the 15th amendment to the u.s. constitution.

it   would try making the   president who would the economy get out of depression picked