On the Sunday of Martin Luther King Day weekend I ran into the mayor of New York City, Bill de Blasio. He was in the checkout line of a New Balance factory outlet store in Brighton, Mass., alone. It was a reminder of how quickly the spotlight shifts away from politicians.

Six months ago, Mr. de Blasio was debating Vice President Biden in prime time on national television. If he wasn’t exactly drawing huge crowds on his campaign visits to Iowa and New Hampshire, well, at least he was followed by a pack of reporters and an entourage of aides, and his failure to generate huge crowds wound up being the topic of news articles read by many people.

Now Mr. de Blasio, while remaining the mayor of America’s largest city, has joined the long list of presidential candidates who did not win the presidency. It’s a distinguished group, but it’s not a club that it’s anyone’s first choice to join.

What are the options for a former presidential candidate? There’s the radio and television personality route chosen by a former governor of Arkansas, Michael Huckabee, who ran for president as a Republican in 2008 and 2016.

There’s the possibility of serving in the cabinet; President Trump named his former opponents Rick Perry as energy secretary and Ben Carson as secretary of housing and urban development. John Kerry got to serve as secretary of state after failing as a Democratic presidential candidate in 2004.

The Senate is always a fallback; Governor Mitt Romney is there, along with former presidential candidates Marco Rubio and Kamala Harris and Lindsey Graham, who were already in the Senate when they made their attempts for a presidential nomiantion.

Vice President Walter Mondale served as ambassador to Japan during the Clinton administration after running unsuccessfully against President Reagan in 1984. Robert Dole and Richard Gephardt became lobbyists. Michael Dukakis became a college professor; Robert Kerrey, a senator from Nebraska who ran for president in 1992, became a university president.

What all these things have in common is that they are considerably less significant than being president of the United States.

If the Democratic presidential candidates are driving you crazy — not in a “how will I ever pick between all of these great choices,” sort of way, but in a “really, this is the best they can come up with?” sort of way, it may be some consolation that before long, most of these characters will be back in the relative obscurity in which they belong.

For the candidates, that may be mentally tough; going through life with the label “losing presidential candidate” is not exactly an ego-booster. Some of them may console themselves with the knowledge that “losing presidential candidate” was a label that also belonged to Ronald Reagan, George H.W. Bush, and Richard Nixon before they earned the label of “winning presidential candidate,” also known as “president.”

The “losing presidential candidate” label can also translate into the title of vice president, as Mr. Biden can attest.

The losers sometimes lose for reasons outside their control. It doesn’t necessarily mean they wouldn’t have made good presidents, or that their ideas lack value. Their presence in a race helps sharpen the skills of the winners and helps the rest of us voters think through the options.

Participation trophies get a bad rap from pundits worried that America is celebrating mediocrity rather than excellence. I thought Mr. de Blasio’s proposed 70% federal income tax would be ruinous and once described him as a “pro-Sandinista tax-the-rich type.” As we head into a primary and caucus season and election year that celebrates winners, though, let us pause to thank the losers, too.

Mr. De Blasio, Beto O’Rourke, Cory Booker, Kamala Harris, Julian Castro — at least part of their motive for risking the humiliation of loss must have been that they cared about America enough to try to improve it.