According to Article II, Section 1 of the CONSTITUTION OF THE UNITED STATES, only executive power is vested in the President.  The President is Commander-in-Chief of the Military, commission all officers, and with the advise and consent of the Senate, make treaties, appoints Ambassadors and other Public Ministers and Consuls, judges of the US Supreme Court an all other officers of the United States and fill vacancies that happen during Recess of the Senate. 

He also receives Ambassadors and other public ministers as well as ensuring all laws are faithfully executed.  Section 3 requires the President to report to Congress information on the State of the Union and make recommendations and under extraordinary circumstances, convenes/adjourns Congress.

The President has no power to change the CONSTITUTION OF THE UNITED STATES.   Under Article V, only Congress may propose amendments (which requires radification by three-fourths of the States) or call a Constitutional Convention.

Regardless of who is elected President, they will be bound by powers granted in the US Constitution.