What is the louisiana purchase and why is it important?

the lousiana purchase was a purchase of a mass of land that doubled the size of the land that was the United States.  It was important because with the new land, the united states could colonize more and boost their economy.  

Explanation:

congress failed to remove johnson. but it did succeed in getting control of efforts to re-build the south following america's civil war. radical republicans wanted to punish the south for starting the war. they also wanted to be sure new governments in the southern states would support the republican party.