Why don't presidential candidates announce their running mates before achieving their party's nomination?

Question

As far as I can tell, a candidate has only announced their running mate before achieving the nomination twice since the modern system of primaries came into use in the 1970s. These occasions were in the extremely close nomination race between Reagan & Ford in 1976, when Reagan announced Senator Richard Schweiker as his candidate for Vice-President, and more recently in 2016, when Ted Cruz chose Carly Fiorina as his running mate. Notably, both candidates were ultimately unsuccessful in achieving the nomination.

Clearly it is permissible to do so, so why don't candidates generally do this? I would have thought that choosing a running mate from a target state would afford a significant advantage in the primaries, given the home-state advantage.

Answer 1

It's an interesting question you're raising. In many cases, the V.P. candidate gets chosen from among the other competitors for the party's nomination of a candidate for President who most helped the ultimate nominee to win the nomination (or at least caused him or her the least amount of damage). We saw the beginnings of this just after the South Carolina Democratic primary this year when Pete Buttigieg and Amy Klobuchar both dropped out and endorsed Joe Biden, as well as a couple days later after Super Tuesday when both Mike Bloomberg and Elizabeth Warren dropped out of the race. Clearly, all might be interested in considering a Vice-Presidential nomination at this point.

However, it's one thing to voice your support for another candidate in order to gain a leg up for the V.P. nomination. It's another thing entirely to actively support the candidate. I suspect in most cases that the nominee wants to actually see what the V.P. candidate brings to the table in terms of on-the-ground support, and they can only see that after watching how they perform in the rest of the primaries up until the convention.

Regarding picking candidates with home state advantage ... sure, home state advantage can be very helpful, but just because someone is from a particular state doesn't necessarily mean they'll bring that state's voters with them. For instance, Warren is from Massachusetts, yet she finished third in the Massachusetts primary on Super Tuesday this year behind both Biden and Sanders. In order to have a home state advantage, you also have to be able to bring victory in your home state.

Also, having a home state advantage isn't equally important in all states. For example, Bernie Sanders has a home state advantage in Vermont, but it's very unlikely that Vermont with its 3 electoral votes will be the difference maker in November. So if Biden wins the nomination, putting Sanders on the ticket due to his home state advantage in Vermont wouldn't be a good idea from the perspective of his home state advantage. He might or might not bring other benefits to the table, but home state advantage isn't one of them.

On the other hand, if the candidate in question were from a state likely to be a toss-up in the general election, such as Florida, Pennsylvania, Ohio, or Michigan, and that candidate had a good likelihood of being able to help deliver that state if named the V.P. candidate, then the home state advantage would definitely come into play.

Since this is more of a rarity than a commonplace event, home state advantage is usually not much of an advantage.

Answer 2

In order to nominate a running mate, you must have someone who is willing to accept that nomination. Sometimes, a running mate is a very personal choice (meaning, specific to that person running); but often, it's a person who would be well suited to run for VP on any ticket. That person, then, is not going to be willing to accept until the nomination is guaranteed, as they'll want to be VP for whomever wins - and at that point you might as well wait until the convention, although undoubtedly the name will be leaked early to make sure there's no surpises.

Could you imagine if Biden called Stacy Abrams and asked her to be his VP today, for example? Even better, let's imagine he called her two weeks ago, before Super Tuesday. Think she'd have said yes? I highly doubt it. She'd have preferred to wait in case Bernie won the nomination - as he might easily nominate her as well - and even Bloomberg might have considered her.

What's more, since it's unusual, it could be seen as a candidate flailing for anything that might help them - implying weakness. For example, when Ted Cruz named a running mate in 2016, it was remarked as:

a last-ditch move to regain momentum after being mathematically eliminated from winning the GOP presidential nomination outright

Schweiker was not much better:

Not to say there weren't problems. A few movement conservatives went ballistic and while some delegates moved into the Reagan column, just as many moved away, including Clarke Reed, chairman of the Mississippi GOP. But the issue of delegates was secondary. The first order of business was to keep Reagan’s campaign alive for three weeks and the selection of Schweiker did this. At one point in Kansas City, faced with conservative criticism, Schweiker offered to resign from the ticket. Reagan ardently refused.

Perhaps keeping the candidacy in the news, but not propelling it to the victory stand certainly.

Ultimately, this is politics; doing things "the way it always has been" is pretty much par for the course; and until this strategy works for someone, I don't expect to see it as common. Of course, if Cruz had won the nomination...