Over time, the power of the presidency has expanded becausepresidents have always enjoyed great popularity and can do as they .the office of the president is important and the nation needs stronger leadership. the constitution intended for this to happen. congress was happy to give up some of its responsibilities.

The office of the president is important and the nation needs strong leadership.

Congress has not typically given up its responsibilities, and at times has had a contentious relationship with presidents as the legislative and executive branches check and balance each other's power.  And while some presidents have expanded the power of the office by their popularity, even presidents who weren't highly beloved by the people have managed to increase the power of the office.  

The nineteenth amendment changed voting rights as it allowed for women to vote nation wide