Over the past 100+ years there has been a gradual concentration of powers in the Executive Branch, making the president nearly as powerful as a king as he directs the activity of more than 580 federal agencies and bureaus.

From the Constitution Article 1, Section 8 Tax (Uniformly)Borrow, and pay debtsProvide for the common defense/general well-beingRegulate foreign commerce and commerce between the statesEstablish citizenship rulesEstablish bankruptcy lawsCoin and regulate money valuesStandardize weights and measuresPunish counterfeitingEstablish a postal systemPass copyright and patent