As cheif executive, a president must do which of the

As a chief executive, the President is the leader for the millions of workers in the government in the Executive branch or office. He or she will be the one to decide how the United States' laws are to be implemented or enforced. He or she will also choose advisors and officials to help him run the Executive office or branch. 

He advocated for a separation of powers of the government and the ones enforcing the law.