Conventional wisdom holds that if the vice presidency matters at all, it matters only in its gestation period: the campaign. And vice-presidential selection has traditionally been attuned to that. Whether a sop to factions that lost the race for the top spot or an attempt to balance the qualities of the presidential nominee, the vice-presidential choice has generally had more to do with winning than with governing.

That was certainly the case with Agnew. Nixon initially chose him in 1968 because, as a moderate governor from a border state, he had both supported the civil-rights movement and made several tough-on-crime speeches. After the election, however, Nixon lost interest. He was eager to dump Agnew from the ticket when he ran for reelection in 1972, but he couldn’t. By then the vice president, with his attacks on the press and the political elites, had become a darling of a different faction: conservatives.

Had Nixon retained the right’s support during his first term, this wouldn’t have been a problem. But his decision to open relations with Communist China, in addition to his support for a raft of liberal social and economic policies on the domestic front, soured his relationship with conservatives. By 1972, they were in open revolt, even running a protest candidate in the primaries, Ohio Representative John Ashbrook. Nixon needed Agnew—not to govern, but to campaign. So Agnew stayed.

Nixon’s desire to dump Agnew stemmed from his belief that Agnew was too ineffectual for the office he held. The irony is that, thanks to Nixon, the responsibilities of the vice presidency had grown considerably by the time Agnew entered the office. Constitutionally, the vice president’s role was legislative, not executive. To the extent that vice presidents did anything in the pre-World War II era, it happened over in the Congress, where the vice president served as the president of the Senate, casting tie-breaking votes and certifying electoral-college counts.

As presidents gained more control over running-mate selection, a transition that began with Franklin Roosevelt in 1940, the office began to transform. The personal selection of a running mate enabled presidents to view their next-in-line as a team member. This was first fully realized during the Eisenhower-Nixon years. As vice president, Nixon abandoned the Senate and took up a number of executive functions, serving on commissions, liaising with Congress, and acting as an administration surrogate at home and abroad.

It was this new executive vice presidency that Agnew was supposed to fill. But while Nixon was happy with the electoral work Agnew did—1968 was a squeaker of a race, and Nixon believed Agnew had helped him win it—when it came to governing, he was deeply disappointed in his vice president.

Take Agnew’s foreign travels, modeled after Nixon’s own extensive globetrotting as vice president. A 1971 trip to Africa turned into a debacle for Agnew. In an Oval Office conversation with Nixon, John Ehrlichman, and H.R. Haldeman, in which the three discussed how to dump Agnew from the 1972 ticket, the Africa trip loomed large. Agnew’s constant golfing was a particular point of contention. “You’ve got to make it appear that the trip’s for work. Not over there on a goddamn vacation,” Nixon fumed.