Twenty-four people are running for the Democratic nomination for president of the United States. From where I sit, at least half of them are only running for exposure, for the vice presidential nod, for cabinet secretary, to push a platform or simply to be seen. Their ambitions have made the process turgid and impractical, often amusing and only sometimes illuminating.

The candidates do best when they have time to expound on their ideas, as they did at the Rev. William J. Barber II’s Poor People’s Congress on June 17 or at the Rev. Jesse Jackson’s National Rainbow Coalition International Convention June 28 through July 2.

Rev. Barber’s meeting drew nine candidates, each of whom had the opportunity to give a 4-minute speech and 26 minutes of questioning from Rev. Barber. The Rainbow PUSH gathering drew seven candidates who had about 15 minutes to address those assembled.

Former Vice President Joe Biden, U.S. Sen. Elizabeth Warren and Mayors Bill de Blasio and Pete Buttigieg had press conferences with Rev. Jackson. U.S. Sens. Kamala Harris and Cory Booker did not attend Rev. Jackson’s meeting, although Sen. Harris did get to Rev. Barber’s and pledged to support a debate dedicated to poverty issues.

With a crowded field and calendar, it is clear that everybody can’t be everywhere, but I’d like the two African-American senators to explain why they snubbed Rev. Jackson, a leader who provided the very foundation for them to run for office.

Memo to candidates Andrew Yang, Marianne Williamson, Montana Gov. Steve Bullock, Mayor Wayne Messam of Miramar, Fla., and a few others: What are you running for, really? You’ve got ideas, but doesn’t everybody? But you have about as good a chance of being president as the proverbial snowball has a chance of surviving Hades. You’ve raised a little money and you’ve got a skeleton staff. Why not sit home and write op-eds about your good ideas? Somebody will publish them.

Memo to Beto O’Rourke: Just like the South lost the Civil War, you lost the U.S. Senate race in 2018. Losing a statewide competition is hardly the foundation for a successful presidential run. You were a nondescript congressman who sponsored little legislation, a Democratic sensation mainly because you came close to toppling the odious Sen. Ted Cruz. But what do you stand for other than white male exuberance, jumping up on tables with the wild hand gestures? Run for U.S. Senate in Texas again. Maybe you’d win and really make a difference!

Memo to Julián Castro: Don’t patronize your own community by speaking Spanish poorly. I think Latino people care more about your policy positions than your Spanish language ability. Good move in going after Beto O’Rourke in the debates on immigration issues. Wrong move in missing the Poor People’s Congress after confirming that you’d be there.

Memo to Joe Biden: You’re better than your act, better than your debate performance, better than your wandering, long-winded speeches. I know you’ve been doing you for a long time, and the wordy gaffes seem to work for you. Actually, they don’t. There’s nothing wrong with saying you made a mistake; nothing wrong with apologizing to Anita Hill, which you haven’t done yet; and nothing wrong with talking about busing unapologetically. If you don’t get your act together, Sens. Warren and Harris are going to make mincemeat out of you.

It’s only July, seven long months before the Iowa caucuses on Feb. 3. And eight months before the delegate-rich Super Tuesday, March 3, when at least 15 states, including Texas and California, will hold primaries and 1,321 Democratic delegates will be up for grabs. What we must know, even at this point, is that all 24 candidates aren’t running for president. At least half of them are simply running for exposure and most of the nation is not paying attention.

The writer is an economist and author.