Why was the monrone doctrine considered a critical document that established the united states as a power in the western hemisphere

It was considered a critical document, because it told many European nations that their tyranny wouldn't be tolerated.

Cherokee  removal, part of the trail of tears, refers to the  forced  relocation between 1836 and 1839 of thecherokee  nation from  their lands ingeorgia, south carolina, north carolina, tennessee, texas, and alabama to the indian territory (present day oklahoma)  in  the thenwestern united states, and the resultant deaths