According to this act, if the president dies or is unable to fulfill his office, the vice president becomes president. Next in line is the speaker of the house, then the president pro tempore of the senate, then the secretary of state and on down the line of the president's cabinet. read more
The 25th Amendment, Section 1, clarifies Article II, Section 1, Clause 6, stating unequivocally that the vice president is the direct successor of the president, and becomes president if the incumbent dies, resigns or is removed from office. read more