As the Framers did not delineate a line of succession for the Vice President or address a vacancy in that office, historically if a vacancy occurred the office would remain empty until the next inauguration. There was no provision for an "acting Vice President", although the title has been used at various times in our nation's history. Since 1789, the office has become vacant 18 times.  In 1967, passage of the 25^th Amendment set the formal procedure for filling a vacancy in the office of Vice President.

The 25^th Amendment states, in part:

"Whenever there is a vacancy in the office of the Vice President, the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress."

The first Vice President to be selected under the 25^th Amendment was Gerald Ford in October, 1973, who assumed the Presidency 10 months later in August, 1974 upon the resignation of Richard M. Nixon.