Ed mentioned this poll in passing in his Zuckerberg post earlier but it deserves its own thread. I’ve overlooked Buttigieg in writing about the primary because we (or at least I) tend to focus on national polls as the best rough measure of the race even though we (er, I) understand that there’s no national primary. There are a series of state primaries, they’re held in a very particular order, and how well one does in the first three or four contests strongly influences one’s chances at winning the nomination. Look at Buttigieg’s national polling and you’ll find a candidate who’s distinguished himself enough to escape the race’s populous bottom tier but who’s never gained enough momentum to crack the top tier. Mayor Pete is a four-percent candidate when he’s polling badly and a seven- or eight-percent candidate when he’s polling better, but it’s been many months since he touched double digits. He just doesn’t seem like a threat to Warren, Biden, Sanders.

If, that is, we were having a national primary. Which we aren’t.

In Iowa, where Buttigieg is devoting most of his energy, the story is different. It hasn’t gotten much attention but he’s been in double digits in five of the last six polls taken there. In three of those polls he’s outperformed Bernie Sanders, who came within a whisker of winning Iowa in 2016. The catch is that, even though his polling in Iowa is stronger than it is elsewhere, he hadn’t quite entered the top tier there either. He’s now reliably in the 14-percent range but either Biden or Warren or both had always polled in the low 20s. It is — or was — a two-person race with Buttigieg a potentially dangerous dark horse.

Until today, that is. This USA Today/Suffolk poll has the race essentially a complete toss-up, with enough uncertainty among caucusgoers to hold every last contender under 20 percent.

The poll, taken Wednesday through Friday, put Biden at 18%, Warren at 17% and Buttigieg at 13% among 500 likely Democratic caucusgoers…

At 37, Buttigieg is the youngest contender in the field, and he is the first openly gay candidate to seek the Democratic Party’s presidential nomination. He has gained ground through strong performances in the Democratic debates: Among those surveyed who watched the debate last Tuesday, 4 in 10 said Buttigieg was the candidate who did better than they expected

Among debate-watchers only, Buttigieg held a narrow lead in the poll, at 19%. Biden and Warren were tied at 17%.

There were other signs of a friendly political landscape for Buttigieg and Warren in the poll. They led the field as the second choice of respondents; Warren was picked by 22% and Buttigieg by 14%.

The number of caucusgoers who say they’re undecided has actually *risen* eight points since the last Suffolk poll there in June, which is not what you’d expect with voters having had four additional months to deliberate on their choice.

How’s Buttigieg doing it? As noted in the excerpt, he’s impressive at the mic. It may be that with more Democrats starting to pay attention to the race as the caucuses approach, more voters will get their first exposure to Buttigieg at the next few debates — raising the possibility that we’re nowhere near his ceiling yet in polling. But he’s doing it the old-fashioned way in Iowa too. Remember that he led all Democratic candidates in fundraising in the second quarter. He’s been putting that money to good use, both in terms of ad buys and assembling a top-notch GOTV team:

Thanks to a nearly $25 million fund-raising bounty in the spring, which he topped up with a respectable $19.1 million over the summer, as reported Tuesday, Mr. Buttigieg has been able to invest in a gold-plated ground game in Iowa as he seeks to challenge two candidates who have been organizing for longer here, Senators Elizabeth Warren and Bernie Sanders…

Grass-roots organizing is essential to a strong caucus finish. Word of mouth about a candidate is often what turns people out on a cold February night. The Buttigieg campaign, which opened its bus tour to live-tweeting journalists in an effort to set itself apart, is also road-testing a somewhat novel approach to organizing. Its Iowa volunteers first contact friends and family members rather than cold-calling lists of registered voters, who are now so bombarded they ignore unknown numbers…

Mr. Buttigieg’s Iowa sweep coincided with the opening of 20 field offices and the hiring of nearly 100 staff members statewide, as robust a build-out as that of Ms. Warren and Mr. Sanders.

Iowa isn’t a must-win for Warren, Biden, or Sanders the way it is for Buttigieg. All three are better known than him nationally and can credibly argue that they’ll rebound in one of the other early states if they disappoint in Iowa. Bernie won New Hampshire in a landslide three years ago; Warren is leading in the polls there right now and reportedly has an amazing field operation in Nevada; Biden is counting on South Carolina’s majority-black primary electorate to put him over the top. Buttigieg needs an Iowa win (or second place) to show he’s for real, though. He’s all-in. And he’s competitive.

He has an advantage over Warren and Sanders there too. Remember that the impeachment process might end up bogging down U.S. senators in Washington for a precious month (or more) as Trump’s trial takes place. Warren and Sanders (and Kamala Harris, who’s looking to Iowa to revive her campaign) will be stuck there every afternoon, six days a week, for several weeks. That’ll leave Biden and Buttigieg alone on the trail during the day in Iowa to press their advantage and build a following. Imagine if House Democrats drag their feet on impeachment, the Senate trial bleeds into January, and Mayor Pete has Iowa to himself in the immediate run-up to the caucuses while Warren is chained to her desk in the Senate chamber. Even if an upset win for Buttigieg in Iowa doesn’t deny Warren the nomination, it could make the race much longer and more expensive for her than it would have been if she’d had a free hand to campaign in Iowa and win the state herself.

By the way, the secret ingredient in Buttigieg’s surge is the destruction of Kamala Harris, who was polling at 16 percent in Iowa when Suffolk checked in on the race in June and is down to three percent there today, tied with Tulsi Gabbard. She’s not the only candidate who’s declined (Biden is down six points too) but Harris’s implosion is spectacular, and still somewhat mystifying to me. She’s not a good retail politician, she’s way too slippery on the issues, but still — from 16 points to three? There must be plenty of former Harris voters in Buttigieg’s tent now, which I suppose stands to reason. If you were with Harris in June, odds are it was because you were uncomfortable for whatever reason with the big three. Now that she’s a nonfactor, many of those voters have transferred their discomfort to Mayor Pete’s tent.

In lieu of an exit question, watch the second half of this CNN report from earlier this afternoon in which Manu Raju reports that the Democratic impeachment timeline may have already begun to slip from Thanksgiving to Christmas. Warren and Sanders really might end up stuck in the Capitol in January.