Which finally abolished slavery in the us?

The Thirteen Amendment to the Constitution finally abolished slavery in the United States.

Explanation:

The Thirteenth Amendment to the United States Constitution officially abolished and continues to prohibit slavery in the United States of America, and, with limited exceptions (such as those condemned for a crime) prohibited involuntary servitude.  

At the time of its ratification, slavery remained legal only in Delaware, Kentucky, Missouri, Maryland and New Jersey. In the rest of the United States the slaves had been freed by the state action and the "Emancipation Proclamation" of the federal government.

Abraham Lincoln (who had promulgated the Proclamation) and others were concerned that the Emancipation Proclamation would be seen as a temporary measure only during the Civil War, and, therefore, in addition to the liberation of slaves in those states where slavery was still legal, they supported the Amendment as a means of guaranteeing the permanent abolition of slavery.

the neutrality acts were passed by the united states congress in the 1930s, in response to the growing turmoil in europe and asia that eventually led to world war ii. they were spurred by the growth in isolationism and non-interventionism in the us following its costly involvement in world war i, and sought to ensure that the us would not become entangled again in foreign conflicts.

the legacy of the neutrality acts is widely regarded as having been generally negative: they made no distinction between aggressor and victim, treating both equally as "belligerents"; and they limited the us government's ability to aid britain and france against nazi germany. the acts were largely repealed in 1941, in the face of german submarine attacks on u.s. vessels and the japanese attack on pearl harbor.