Nate Silver: “As much as we try to remind you all about how uncertain elections can be — pleas that sometimes fall on deaf ears — it’s important to keep in mind in advance of the Iowa caucuses. To begin with, primaries are much harder to poll than general elections, and caucuses are even harder to poll than primaries, as they introduce a number of complications. Caucuses require a long time commitment, which can make turnout harder to predict. They aren’t a secret ballot, so voters can literally try to persuade their neighbors to change sides. And Iowa Democrats employ a viability check that asks voters to switch candidates if their first choice doesn’t clear a certain threshold, usually 15 percent of the vote at that caucus site. That makes second choices important, and even opens up the possibility of strategic alliances between the candidates.”

“So even though Bernie Sanders and Joe Biden are doing a bit better than other Democrats in Iowa polls, everyone would need a bit of luck to win the caucuses. Per our model, as of 8 p.m. Wednesday, Sanders had a 37% chance of winning the most votes — which is the best in the field. But it also means there’s a 63% chance he won’t win.”

A new Monmouth poll in Iowa finds Joe Biden leading the Democratic presidential race with 23%, followed by Bernie Sanders at 21%, Pete Buttigieg at 16%, Elizabeth Warren at 15%, Amy Klobuchar at 10%, Tom Steyer at 4% and Andrew Yang at 3%.

But most interesting is that just 47% of likely caucusgoers say they are firmly decided on which candidate they will support.

Said pollster Patrick Murray: “Caucus electorates are the most difficult to model in polling. The smartest takeaway from this, or any Iowa poll for that matter, is to be prepared for anything on Monday.”

Also important: “The poll asked caucusgoers to name a candidate they have in mind as a second choice. When these are combined with initial preferences, Biden (39%), Warren (34%), Sanders (32%), and Buttigieg (29%) are bunched together. They are trailed by Klobuchar (22%), Steyer (10%), and Yang (7%) as either a first or second choice.”

Playbook: “Joe Biden is cycling three new ads into his $4 million Iowa ad buy. It’s a six-figure buy that will run in the Des Moines, Cedar Rapids, Quad Cities and Sioux City media markets.”

“The first ad is Soul, which reiterates Biden’s message that the fabric of American society will change if Trump has another four years in office. Integrity has testimonials from people about Biden’s character. They also have a 15-second spot, Enough which has a Des Moines firefighter praising Biden.”

A new Iowa State University poll finds Pete Buttigieg leading the Democratic field with 26%, followed by Elizabeth Warren at 19%, Bernie Sanders at 18% and Joe Biden at 12%.

Warren has dropped by nearly 10% over the past month.

Said pollster Dave Peterson: “Warren has seen heightened scrutiny this past month, while Buttigieg has received mostly positive attention. A little over 60% of the people who supported Warren in October still support her now, and those who switched went to Buttigieg.”

A new Monmouth poll in Iowa finds Pete Buttigieg leading the Democratic field with 22%, followed by Joe Biden at 19%, Elizabeth Warren at 18% and Bernie Sanders at 13%.

They are followed by Amy Klobuchar at 5%, Kamala Harris at 3%, Tom Steyer at 3%, Andrew Yang at 3%, Cory Booker at 2%, and Tulsi Gabbard at 2%.

However, just 28% of likely caucusgoers are firmly decided on their candidate choice.

Said pollster Patrick Murray: “Iowa caucusgoers are used to changing their minds up to the last minute. In fact, some probably even look forward to waiting until caucus night to settle on a candidate. This all translates to a race that is extremely fluid and will probably stay that way up to February 3rd.”

A new Quinnipiac poll in Iowa finds Elizabeth Warren leading the Democratic presidential race with 20% support among likely caucus-goers, followed by Pete Buttigieg at 19%, Bernie Sanders at 17% and Joe Biden at 15%.

The top four are followed by Amy Klobuchar at 5%, Kamala Harris at 4%, and Tom Steyer, Tulsi Gabbard, and Andrew Yang are each at 3%. No other candidate tops 1%.

“Joe Biden risks a humiliating third or fourth-place finish in Iowa early next year, according to nearly a dozen senior Democrats in the state who attribute it to what they see as a poorly organized operation that has failed to engage with voters and party leaders,” Bloomberg reports.

“With fewer than 100 days until the Feb. 3 caucuses, Biden is failing to spend the time with small groups of voters and party officials that Iowans expect and his campaign’s outreach has been largely ineffective, according to 11 senior Democrats in the state. They worry that could send Biden to a crippling loss behind Elizabeth Warren and Pete Buttigieg, who have highly organized campaigns in Iowa, said the Democrats.”

A new Iowa State University/Civiqs poll finds Elizabeth Warren leading the Democratic presidential field with 28%, followed by Pete Buttigieg at 20%, Bernie Sanders at 18% and Joe Biden at 12%.

The poll of likely caucus-goers also asked voters to list the candidate they do not want to win the nomination. Biden and Sanders topped this list with Tulsi Gabbard third.

Elizabeth Warren has surged in Iowa, narrowly overtaking Joe Biden and distancing herself from fellow progressive Bernie Sanders, the latest Des Moines Register/CNN/Mediacom Iowa Poll shows.

Warren leads with 22%, followed by Joe Biden at 20%, Bernie Sanders at 11%, Pete Buttigieg at 9%, Kamala Harris at 6%, Amy Klobuchar at 3% and Cory Booker at 3%.

Polling at 2% are Tulsi Gabbard, Beto O’Rourke of Texas, Tom Steyer and Andrew Yang. Eight others are polling at 1% or less.

Said pollster Ann Selzer: “This is the first major shakeup. It’s the first time we’ve had someone other than Joe Biden at the top of the leader board.”

She added: “The data in this poll seem to suggest the field is narrowing, but my sense is there’s still opportunity aplenty. The leaders aren’t all that strong. The universe is not locked in.” 

Results of a new Des Moines Register/CNN/Mediacom Iowa Poll on Democratic presidential candidates will be released online at 8 p.m. ET Saturday, the Des Moines Register reports.

A new Iowa State University/Civiqs poll in Iowa shows Elizabeth Warren leading the Democratic presidential race with 24%, followed by Joe Biden and Bernie Sanders tied at 16% each.

Key takeaway: “Almost a third (31%) of those surveyed said they do not want Biden to win the nomination, followed by Sanders (23%) and Williamson (12%).”

A new Focus on Rural America poll in Iowa finds Joe Biden barely ahead of Elizabeth Warren, 25% to 23%, followed by Pete Buttigieg at 12%, Bernie Sanders at 9%, Amy Klobuchar at 8% and Kamala Harris at 5%.

Joe Biden’s campaign said Iowa is not a must-win state on the former vice president’s path to the Democratic presidential nomination and signaled that the campaign is already “ramping up” its Super Tuesday efforts, Politico reports.

Said the adviser: “Do I think we have to win Iowa? No… We think we’re going to win. We think it’s going to be a dogfight…. But we think there are several candidates in this field, there’s probably three or four, that are going to go awhile.”

NBC News: “First, it was Kamala Harris. Then, Joe Biden. Now, Pete Buttigieg.”

“All three are suddenly running ads on the air in Iowa, signaling both a new, quicker pace in the race for the 2020 Democratic presidential nomination and what Democratic insiders say is a need to check the formidable ground game of Massachusetts Sen. Elizabeth Warren.”