(Melina Mara/The Washington Post)
Opinion writer

Presidential primary campaigns are not fair. Well-qualified candidates struggle to get their message out. Demagogues find a ready audience. Self-fulfilling prophecies by the media elevate some and kneecap others. The campaign is often absurdly disconnected from the actual job that a president does. When it’s over, we almost never say, “Well, that went well.”

The purpose of the whole thing is for a party not just to pick a champion but to decide who it is and what it wants for the future. And in that way, as messy as the process is, it usually works. Donald Trump really did represent who Republicans were and what they wanted in 2016, just as Barack Obama did the same for Democrats in 2008.

And right now — still with 6½ months to go before the first vote — the field of 25 Democrats running for president is coalescing into a shape.

Each poll that comes out tells us something slightly different. But if you step back and view the broader picture a pattern is pretty clear.

For instance, an NBC News-Wall Street Journal poll that came out yesterday has Joe Biden at 26 percent support, Elizabeth Warren at 19 percent, Bernie Sanders and Kamala D. Harris tied at 13 percent, and Pete Buttigieg at 7 percent. The latest Economist-YouGov poll shows a similar spread: Biden 22 percent, Warren 17 percent, Harris 14 percent, Sanders 11 percent.

If you want to pore through every recent poll, you can find them all gathered at FiveThirtyEight or RealClear Politics, but here’s how I would sum up what’s happening at the moment:

  • Biden, who entered the race polling at nearly 40 percent, is dropping — but he’s still in the lead.
  • Warren has the most momentum; she now appears to be in second place.
  • Sanders is on a long, slow decline; having been the alternative to Biden all along, he’s now in danger of being passed by others.
  • Harris comes in next.
  • Buttigieg follows her, but it’s unclear if he’ll be able to garner more support despite his eye-popping fundraising.
  • Everyone else is struggling mightily.

Let’s talk for a moment about those stragglers, because what’s remarkable about them is that they aren’t getting more support. Even setting aside the ones who have no business running for president, it’s an extremely appealing group. Just among those garnering about or less than 1 percent, you’ve got four senators and three sitting or former governors, all of whom have demonstrated their appeal to voters by winning multiple races. They’re generally smart and accomplished people.

But now they’re caught in a trap. If you’re, say, Sen. Kirsten Gillibrand (N.Y.), about now you’re finding it very hard to get media coverage, because reporters and editors say that, because you’re at 1 percent, they’re going to put their limited resources into covering other candidates.

Because voters aren’t seeing you in the news, they don’t think much about you. Even if their opinions are mushy, when asked by a pollster who they’re leaning toward, they’ll name one of the candidates getting more attention. That will then determine who gets coverage going forward. So a voter paying attention to the race hears a lot about the candidates who are polling highest and very little about those who aren’t.

Now it’s possible, if you have a certain kind of dynamism, that you could make enough converts on the ground to push your way past that. But even very capable politicians can’t always pull that off. Sen. Michael F. Bennet (D-Colo.) might be able to be a fine president, but few voters leave one of his events saying, “Oh my god, he’s incredible. I will quit my job to work for that man.”

Nobody’s saying that about Biden either, but he started off with enough goodwill that he doesn’t have to light up the campaign trail like a supernova of charisma. His problem is that his candidacy has mostly been a series of missteps and controversies, and he doesn’t seem to be picking up many new supporters.

But Warren is. And here’s another secret: Reporters would love a race that came down to Warren and Biden. We love contrasts. Biden says the problem is President Trump; Warren says Trump is a symptom of a larger rigged system. Biden wants modest change; Warren wants radical change. Biden is as establishment as it gets; Warren isn’t exactly an outsider, but she ticks off enough insiders to make it seem like she might be.

There’s still time for other candidates to increase their support and join that top tier. But the campaign is ruthless. Once story lines are established, they create hooks for both reporters and voters to understand the race and what it represents.

If you’re a moderate, everything that’s happening now is encouraging you to gravitate toward Biden and not, say, former Colorado governor John Hickenlooper or Sen. Amy Klobuchar (Minn.), whose ideological profiles are similar to his. If you’re interested in sweeping change, what you see in the news makes you think that Warren and perhaps not Sanders is the right vehicle for that change. While unforeseen events can alter the landscape, that encouragement will become only more emphatic as time goes on.

To repeat, it’s not fair. But the choices are going to become fewer very soon.

Read more:

George F. Will: Michael Bennet might be the Democrats’ best chance to beat Trump

The Ranking Committee: Who in the world is Kamala Harris, anyway?

Jennifer Rubin: The one quality that will determine the Democratic nominee

Paul Waldman: Why gender will define the 2020 election