Former vice president Joe Biden delivers the eulogy at the John Dingell funeral at the Church of the Divine Child on Tuesday in Dearborn, Mich. (Carlos Osorio/AP)
Opinion writer

Depending on which confidant of former vice president Joe Biden you speak with or which report based on unidentified Biden allies you read, you might be convinced that he’s all but signed the lease for the Biden 2020 presidential campaign headquarters; you might also hear that Biden, who can be notoriously indecisive, is still conflicted about running.

As we have noted, Democrats would give up some advantages running a septuagenarian nominee and lifetime politician against President Trump. However, Biden is correct when he says that few American politicians know more about the presidency and the Senate. He knows policy (whether you agree with his positions or not), personalities and process backward and forward.

Maybe there is a better role for Biden than candidate. There are plenty of the latter. Instead, why not have Biden be the reality check at debates? And that’s where Democrats could use some of that Biden experience.

The first pair of 12 Democratic primary debates has been set for June, with as many as 10 candidates on each of two successive nights. In addition to logistics (Who stands where? How can you have an interactive conversation with 10 people?), Democrats need to address two potential problems that could undermine voters’ ability to pick the best possible candidate.

To begin with, Democratic voters and the candidates themselves badly want to avoid a negative, destructive primary. And yet someone has to be pushing their opponents. "How do you think you’ll get 60 votes for that in the Senate”? “What do you think the military brass will say when you announce a 5 percent budget cut?” No wants to be the killjoy, but candidates need to be forced to grapple with unpleasant political truths — and demonstrate how they will navigate around obvious barriers.

A related problem is the reflexive race to the left — the distressing pattern in which one candidate stakes out a rigid, absolutist position and then a pack of others declares, “Me, too!” What’s missing is the voice querying candidates as to how their super-ambitious ideas will work in practice.

That’s where Biden can come in. If not as the moderator (one fears he’d talk more than the candidates), why not cast him as a kind of Greek chorus? When someone says something daft (If we can put a man on the moon, why not eliminate fossil fuels?) and other candidates don’t step in to critique the idea, Biden can be the skeptic or the party’s institutional memory. He might interject at key moments questions no moderator is likely to ask: Do you think people in Ohio and Michigan are going to cheer the Green New Deal? When Senate Majority Leader Mitch McConnell (R-Ky.) tells you he’s not bringing your judicial nominees up for a vote, what are you going to do?

Biden can also talk frankly to primary voters. If not endorsing a candidate, he surely can defend fellow pragmatic moderates from attack from the left. If not telling voters whom to vote for, he can surely tell them what to avoid (e.g. praise for Bashar al-Assad).

In sum, Biden’s age and longevity are detriments as a candidate, but as a senior statesman and respected voice, he might help to keep the debates — and the primaries — from going off the rails.

Read more:

Jennifer Rubin: There’s a problem with Biden’s rationale for a possible 2020 run

Paul Waldman: Joe Biden says he’s ‘most qualified’ to be president. So what?

Jennifer Rubin: Biden matters most of all

Jennifer Rubin: Biden has set the bar high for Democratic presidential contenders

Dana Milbank: Stop the bidding! This Democratic presidential candidate is about to clear the field.