Robert fulton is known for inventing

the cotton gin
the mechanical reaper
the steamship engine
machine tools

Robert Fulton is known for inventing the steamship engine.

Explanation:

Robert Fulton was an American engineer, entrepreneur and inventor, known for developing the first steamboat, which became a commercial success.

Considered to be the creator of the steamboat, he was in fact the one who, thanks to his engineering skills, managed to make a previously known process really operational. This same engineering talent led him to realize, taking into account the invention of David Bushnell, the first military submarine.

d.he wanted to send diplomats to communist countries.

the south did not want the federal laws to overrule the state laws.