Answer:
They made this branch the most powerful branch of government.
Step-by-step explanation:
The Executive arm of government deals with enforcing the law and negotiating foreign agreements.
The President of the United States which included Franklin Roosevelt and Truman during the World War II and Cold Period were mostly involved in representing the best interest of the people by taking decisions. This sole decision making made the executive branch very powerful. Other branches of government such as the Legislative and Judiciary have very little or no function when it deals with foreign affairs.