By Jennifer Rubin

If you remember the Agatha Christie mystery in which 10 people mysteriously die one after the other, then the Democratic debates are the opposite.

To the likely chagrin of the Democratic National Committee and many viewers, it will be, at the very least, a full stage for the September debate, although it may be a single night.

Julián Castro qualified on Tuesday and will join former Vice President Joe Biden; Sen. Cory Booker; Mayor Pete Buttigieg of South Bend, Indiana; Sen. Kamala Harris; Sen. Amy Klobuchar; Beto O’Rourke; Sen. Bernie Sanders; Sen. Elizabeth Warren; and entrepreneur Andrew Yang.

Given the number of candidates, one might expect a repeat of past debates, lots of interrupting, a choppy and hard-to-follow discussion and too much baiting candidates to criticize each other. However, there are a couple of reasons to hope the conversation might be more intelligible and informative.

To begin with, while the field ideally might have gotten down to a more manageable six or seven contenders, the rules did mean the apparent elimination of minor, desperate candidates with an incentive to grandstand (I’m looking at you, Mayor Bill de Blasio, and you, Rep. Tulsi Gabbard) and to attack leading candidates. Moreover, the candidates toward the bottom of the heap (e.g. Klobuchar, Booker, O’Rourke) tend to be campaigning on niceness and civility, making them poor prospects for bomb-throwing.

Moreover, we have seen direct attacks don’t work very well or for very long. Harris is paying a price for having gone after Biden for a second debate (although the media narrative that she is in grave trouble is entirely unwarranted). Although Castro has made it under the wire to qualify for this debate, his assault on other candidates for insisting that illegal immigration remain illegal didn’t boost him noticeably.

If we are lucky, the ideological lineup among at least these 10 candidates favors moderates who are advancing reasoned arguments. In other words, there is critical mass of center-left candidates (Biden, Buttigieg, Harris, Booker, Klobuchar and O’Rourke) to make the case that this is a contest not to make the biggest change but rather to do the most for the most people, many of whom don’t want their lives upended unnecessarily.

We hope that under these circumstances, the Medicare-for-all crowd won’t get away with dismissing the majority of people on stage as timid or lacking bold ideas. One would hope that they’d be compelled to answer on the merits and explain why no choice (single-payer) is better than a choice for Medicare, and why, when many European systems don’t eradicate private insurance, we should. Likewise, there are a batch of candidates who think waving a wand to wipe out student debt is a bad idea because, among other things, it doesn’t focus on those who need it, does nothing for the majority of Americans who don’t go to college and posits that working-class people (via taxes) should be subsidizing rich kids and elite universities.

Now, provided we don’t get an 11th candidate whose presence would necessitate a second night and yet another round in which top candidates don’t all appear together, the best part of the September debate may be the ability for voters to compare and contrast all the contenders. Is Warren actually better than Sanders in explaining progressive ideas? Do we want an inspiring speaker like O’Rourke, or do the times demand a worker bee like Klobuchar, or could we get one candidate with some of both?

In short, the stage will still be too crowded for my tastes, but if the number is kept to 10, we’ll at least have ended the ordeal of two nights and have a shot at a more reasoned, informative debate.

Jennifer Rubin writes for the Washington Post.