I assume you mean the President of The United States, not to disparage out of hand all other nation-states with a President. A consideration I emphasize because we must begin to respect a plurality of humanity, away from attempted totalitarian monisms of control.
The single most important task I would perform is to implement a much better thesis to determine what can be discovered (Einstein), with a new operating system for humanity (I have developed) carrying a thesis designed to assign the merit of money only to the strengthening of the renewal of humanity. This task can be achieved by infusing new evolutionary principles in every one of our current manmade systems, requiring no constitutional change. Such a move will impact everything we do without requiring everyone to change. No scorched earth approach is needed.
The name of our evolutionary game must change. As humans equipped with supreme intelligence, we owe it to ourselves to prove we can outlive a common fly. Our current trajectory, stuffed with hollow evolutionary milestones referred to as the American Dream, leads to dying the wealthiest man in the cemetery, as opposed to strengthening the renewal of humanity.
The role, wherewithal, and impact of our presidency must be elevated, away from downstream suboptimization of an existing norm towards higher-order humanitarian goals in compliance with evolution upstream. For if humanity does not comply with nature’s rules, our lifespan on earth will be extremely short-lived. Worse, on our current path, the most intelligent animal on earth is bound to live the shortest. So, it behooves the leader of the “free world” to define and act upon the very freedoms stipulated by nature, the ones all our manmade systems must be subjugated to.
In short, a Presidency’s role must change from the arbiter of a game of soccer, with windshield wiper relevancy, to redefining what gameplay serves the strengthening of humanity, and lead the world by example, with new standards of excellence we first and successfully apply to ourselves.