Henry Clay's Missouri compromise was significant because: It kept the balance of slave states and free states equal. Clay was also known as "Great pacificator" for his work on developing components on the Missouri compromise.
The Missouri compromise was a measure that passed by the U.S congress and allowed the admission of Missouri as the 24th state and Main as a free state in 1821.
Although the compromise measures appeared to settle the slavery issue, the sectional conflict grew until it became a civil war when the compromise was repealed by the Kansas Nebraska Act in 1824. For this, it is said that this event led to the American Civil War.