From the column:

I trust them to reach a majority decision at the convention after a public and substantive process like this one, and you should, too.

I don't.

Oh, I mean eventually they'll "reach a majority decision." I just don't share Carville's unexplained optimism that this decision will have any more legitimacy, or be any less vulnerable to attacks as being the result of power brokers and bigwigs putting in the fix. None of them will have the legitimacy that gets conferred by being chosen in a primary election. They'll be chosen by delegates, who are all party insiders and bigwigs and donors and Democratic officials. That doesn't change whether you have a few town halls or not.

Those delegates aren't a representative cross-section of ordinary Democratic constituents. They're political creatures. They're not likely to base their vote on the outcome of a few town halls anyway, but rather the domestic politics that dominate their lives the other 362 days a year.

Back in February, Ezra Klein did an interview with political insider Elaine Karmack, talking about how an open convention might operate (Klein being a Democratic-leaning pundit who's been pounding the table for Biden to step aside for a while now). Here's what she noted, among a number of interesting observations:

So one of the things I can tell you that most people don’t realize is, I’ve been a delegate to 10 Democratic conventions, and I’ve sat in the delegation. And you’d be amazed how little of the conversation has to do with the presidential candidate.

As Tip O’Neill said, all politics is local. So for all the years I sat in the Massachusetts delegation, I don’t think I ever had a conversation about the presidential candidates. It was all about who’s going to be the next speaker of the house, how many seats do we think we can pick up in the legislature, who’s going to run for attorney general. It was all local politics.

Now, given that it’s so local politics, people who are powerful in the state are going to be the ones that can most easily sway the delegates. So a sitting governor is going to be very important. If you don’t have a sitting governor but you’ve got, say, one United States senator, that person’s going to be very important.

nytimes.com - Ezra klein podcast elaine kamarck

So, for example, the California delegation isn't going to choose between Harris and Newsom based mostly on their town hall performances - or really any aspect of their suitability to be President. It will be based on consideration of California politics and which local power players get behind which candidates and how it helps/hurts their respective teams in California politics. And California has 496 delegates, with only 1,968 needed for the nomination.