Iowa, of course, was supposed to shake up the Democratic presidential race and provide some clarity for Granite Staters. Iowa notably did not do that. When the final results came in on Thursday, it provided a muddled result that even Democratic National Committee chairman Tom Perez said would be under review .

Not since Jimmy Carter and Ronald Reagan’s second general election debate could a television forum be this important, both in terms of its impact on the race in the short term, and the country in the long term.

There is no other way to put it: Friday night’s Democratic presidential debate in New Hampshire could be the most consequential campaign debate in four decades.


So now seven candidates will take the stage for a three-hour debate sponsored by ABC News, its New Hampshire affiliate WMUR-TV, and Apple News, beginning at 8 p.m. Four of the seven candidates could conceivably win New Hampshire.

If history is any guide, this New Hampshire debate could easily determine the winner, particularly in a race this close.

Here are three things to watch:

What will Joe Biden do?

Biden has thought about running for president every presidential year since 1980. He has actually run three different times, 2020 being the third. If he doesn’t pull off a game-changing performance in this debate — something he has never done before in his career — he will likely never be president.

If this seems dramatic, consider that it appears Team Biden understands the stakes. There are only eight days between Iowa and New Hampshire; every day matters, and Biden decided to be off the campaign trail for two entire days while he prepped for the debate.

Biden’s whole 2020 brand is that he is electable. Yet, he came in fourth in Iowa. He is now basically tied for third in New Hampshire with Elizabeth Warren, and trails Bernie Sanders and Pete Buttigieg.


The debate is set up for Biden to take out Buttigieg somehow — both to lift up his own poll numbers, but also to just stop Buttigieg from his surge to be the moderate option for Democratic voters down the road.

There is precedent for this. Four years ago, then-New Jersey governor Chris Christie basically ended Marco Rubio’s surge in this pre-New Hampshire primary debate.

Buttigieg, of course, knows all of this and will be prepared. But this is the biggest dynamic to watch.

The curious case of Bernie Sanders

What to do with Sanders has been a hard question all year. While Buttigieg will have a big target on his back as the apparent winner of the Iowa caucuses and the one surging in New Hampshire, Sanders is the one who has been leading here for months. Oh, and he won the primary in 2016.

But, for the most part, no candidate has really attacked Sanders. Polls have found he is one of the most popular politicians in America, so that might have something to do with it. Then again, he might have that status because no one has ever taken him on in a sustained way.

While Buttigieg and Biden might be the featured battle, Warren needs to win in New Hampshire and to do so she needs to go through Sanders.

Warren may decide to hold her fire on Sanders again, but then does that mean Sanders, the front-runner, will go untouched? This is where you can see someone like Buttigieg trying to pivot away from a sinking Biden to create a two-person contest with Sanders. They did, after all, basically tie in Iowa and are statistically tied in New Hampshire polls.


One last thing: Watch Amy Klobuchar here. She has suggested exasperation over Buttigieg’s rise and saying that no female mayor of South Bend, Ind., could be a leading contender for president. But Bernie remains her perfect foil. And she has nothing to lose.

Can Warren have a breakout performance?

Like Biden, Warren needs a huge performance in New Hampshire in order to be a serious 2020 contender going forward. In fact, beyond doing well, Warren needs to win the Granite State.

If a Warren comeback is going to happen, it will need to happen before the debate ends. There will be no larger audience before primary day and it is very hard to break through the media environment in the state, particularly as President Trump comes into New Hampshire on Monday for a primary eve rally.

James Pindell can be reached at james.pindell@globe.com. Follow him on Twitter @jamespindell.