between 1854 and 1861, kansas proposed four state constitutions. out of the four proposed constitutions, three did not allow slavery. finally, in july 1859, kansas passed the wyandotte constitution, which was anti-slavery. the constitution for statehood was sent to the u.s. government in april 1860 to be voted on. the constitution was passed by the house of representatives, but rejected by the senate. this is because southern voters in the senate did not like that kansas would become a state without slavery. in 1861, after the confederate states formed, the constitution gained approval from the union, and kansas became a state.