In 1861 what major crisis challenged the constitution and our nation

States decide to leave the union

Explanation:

Upon the election of Abraham Lincoln, southern states started leaving the union before Lincoln’s inauguration. It took the Civil War to settle the question of succession.

The issue of slavery in the Southern states of the country. Northerners supported abolitionism but the Southern states depended so much on slavery to grew crops in the large plantations of the South to export those crops. Other issues were the four-way election of 1860, the fugitive slave law, and the feasibility of secession in legal ways from the Union. The United States lived in so much tension during those years and this represented the preamble of what would be the beginning of the American Civil War.

Explanation:

all freedom fighters demanded for constitution. so british finally granted india it's freedom. then a constituent assembly was formed. it's chair man was rajendra prasad and its deputy chairman was dr. br ambedkar.

this assembly take the time of about one year than our constitution was finally formed.

explanation: