Ten candidates are too many. That is the leading impression from the two televised debates involving the Democratic presidential candidates, first in June on MSNBC and then this week on CNN. The 10 actually represent a winnowing, down from the nearly two dozen in the race, the 20 qualifiers spread over two evenings. Wasn’t the lesson learned in 2016, when the Republican debates teemed with candidates and the sessions seemed more like reality television or a prize fight than an effort to enlighten viewers about those seeking to lead the country?

The mass of candidates invites problems with the format, moderators prone to cut off candidates in the interest of fairly dividing the limited time, inviting conflicts that lead to canned zingers yet leave viewers confused about what really are the differences. U.S. Sen. Elizabeth Warren of Massachusetts and Pete Buttigieg, the mayor of South Bend, Ind., are skilled at explaining clearly their thinking in short passages. Does that make for a better president?

Perhaps it does, in part. Yet in these debates, it becomes almost solely defining. It would seem an improvement to reduce the number of candidates per setting to, say, five, and make the gathering closer to a probing conversation.

In that way, there may be less “gotcha!” and more explanation, for instance, shedding light on the stakes between Medicare for All versus building on the achievements of the Affordable Care Act. On Wednesday evening, the early exchange between former vice president Joe Biden and U.S. Sen. Kamala Harris of California on their health care plans must have left many viewers wondering: What are they saying? How do their approaches actually differ? What would that mean for us?

There have been helpful moments, especially in clarifying positions on whether crossing the border illegally should be treated as a civil or criminal violation. Yet, in this case, too, a more expansive format would be productive. It may assist in keeping things from getting stuck in the past, mandated busing serving as the most prominent example. U.S. Sen. Michael Bennet of Colorado rightly expressed frustration about the lack of attention to today’s public schools, in many instances as racially segregated as they were four decades ago.

That isn’t to say Joe Biden deserves a pass on his record from long ago. His decision-making matters, and he could do a much better job explaining his thinking. Yet the format should be more conducive to candor and fleshing out just who these candidates are.

All of this adds up to the obvious: This field must get smaller. That will happen, apparently, as part of qualifying for the stage in September. Then, the debate among the candidates can sharpen and deepen, in particular, over the direction of the Democratic Party going into this crucial election — moderate or more progressive, more center or to the left.

Some candidates even have jabbed Barack Obama (through his surrogate Biden) for not being progressive enough. Much of that is politically expedient. Yet this element and other aspects of the party could be explored more effectively with fewer candidates and more time.

With that in mind, Elaine Kamarck of the Brookings Institution cited some revealing numbers in the wake of the debates this week. Democrats prevail by attracting moderates. In the four presidential elections the party has won since 1980, Bill Clinton and Barack Obama captured more than 60 percent, or close to it, of the moderate vote. In losing, the share has slipped into the lower 50s as a rule. That’s something for the party and its candidates to keep in mind in this campaign, no matter how many are running or how they debate.