Roosevelt was determined to work as a conservationist, and back then global warming was not even discovered. It was important back then to set an example and start working for the earth for a change. Nowadays, after decades and decades of pollution and registering sea level rising and hotter temperatures, it's more important than ever to continue the conservation philosophy. There are several species that existed back in Roosevelt's time that are already extinct, so taking care of parks, forests, lakes and earth it's more essential now than ever.
Necessary and Proper Clause
There were many hostile indians in the area
