The united states gained control of the land it needed to build the panama canal by

The US gained control of the land it needed to build the Panama canal by encouraging independence of Panamian people.

Explanation:

The revolution of independence of Panama was backed by US Panama canal company. Through this encouragement by US Panamanian demand for independence from Columbia. There was a treaty signed by the US based company for making of Panama Canal.

The US ratified this treaty but due to fear of losing sovereignty, Columbia refused to accept it. The Panama canal declaration passed in 1999.