It’s caucus day in Iowa! Here’s what to watch and what the polls show. We also take a look at where New Hampshire stands eight days before the primary. And Republican party activists nationwide seem to have warmed to the idea of Donald Trump. This is HuffPollster for Monday, February 1, 2016.

HERE’S WHAT TO WATCH IN IOWA - HuffPollster: “Both the Democratic and Republican races are close contests in Iowa, and pollsters say surprises are likely. So although businessman Donald Trump has opened up a lead on the GOP side and Hillary Clinton still narrowly leads on the Democratic side, there’s a lot of room for change going into Monday night’s caucuses. Unlike primaries, in which voters simply cast a ballot, caucuses are essentially community meetings. Their outcomes, polling shows, depend on turnout, persuadable voters and late momentum shifts.” [HuffPost]

Polls show leads for Clinton and Trump - More from HuffPollster: “The final Iowa pre-caucus poll from the highly regarded Bloomberg/Des Moines Register/Selzer poll finds businessman Donald Trump and former Secretary of State Hillary Clinton leading in their parties' contests. In the Republican caucus, Trump leads Texas Sen. Ted Cruz, 28 percent to 23 percent. In the Democratic caucus, Clinton leads Sen. Bernie Sanders (I-Vt.), 45 percent to 42 percent.” Recent polls from NBC/WSJ/Marist and Monmouth University show very similar results, as does Quinnipiac on the Republican side. Quinnipiac has Sanders up by 3 percentage points on the Democratic side. The HuffPost Pollster averages show a 7-point lead for Trump and a 4-point lead for Clinton. [HuffPost, Marist, Monmouth, Quinnipiac]

Persuadable voters? - If caucusgoers do shift their preferences on Monday night, Cruz and Rubio could finish higher than the polls indicate. The DMR/Bloomberg/Selzer poll shows that 17 percent of Republicans have Cruz as their second choice, and 1 in 5 would choose Rubio second. The poll also reports that while 55 percent of likely Republican caucus-goers have made up their minds, 45 percent could be persuaded. On the Democratic side, Clinton is the second choice for 26 percent of Democrats and Sanders is second for 28 percent. A big unknown is where Martin O’Malley’s supporters will go in the caucuses where he fails to reach the 15 percent threshold. [DMR/Bloomberg/Selzer, Bloomberg]

Watch live election results tonight on HuffPost.

RELIGIOSITY, NOT RELIGIOUS AFFILIATION GUIDES VOTE CHOICE IN IOWA - Anne Pluta: "Marco Rubio’s plan for the final days before the Iowa caucuses, according to The Washington Post, is to talk about God … a lot. And with all the focus on the evangelical Christian vote in Iowa — they make up nearly 60 percent of Republican caucus-goers and are credited with powering Ted Cruz into the top tier of the race — Rubio’s plan isn’t surprising. But the media’s focus on evangelical Christians misses the larger story: The best predictor of vote choice, according to work by political scientists Robert Putnam of Harvard and David Campbell of Notre Dame, is religiosity, not religious affiliation; Putnam and Campbell call it the 'God gap.' Religiosity, as the two describe it, includes the three B’s: belonging, behaving and believing. The stronger a person’s sense of belonging, the more frequent her church attendance and prayer, and the stronger her belief, the greater her religiosity is." [538]

REPUBLICAN ACTIVISTS NOW SAY DONALD TRUMP IS THEIR BEST SHOT TO WIN - HuffPollster: "The most politically active members of the Republican Party have warmed to Donald Trump’s bid for the party’s presidential nomination since last summer, according to a new Huffington Post/YouGov poll, which finds 68 percent now think he could win the general election. While most surveys attempt to reflect the entire electorate, this one is the latest in a trio of polls focusing solely on Republican activists: well-informed party stalwarts who've run for or held office, served as party officials, worked on campaigns or volunteered their time before elections.Their views shouldn't be seen as representative of the horserace as a whole, but they provide some insight into the role of GOP political leaders in an election cycle where public opinions have repeatedly flouted the establishment. With days until the Iowa caucus and only a scattered handful of endorsements coming from elected officials in Washington, there are increasing signs that the Republican establishment is losing its grip on its activist base." [HuffPost]

Explaining Trump's rise to success - Kirby Goidel and Keith Gaddie: "It is unclear if Donald Trump has rewritten the rules of political campaigning but he has unquestionably left pundits and political scientists baffled by his success. Most careful observers of politics (present authors included) believed Trump would have washed out quickly and decisively. His seemingly off-the-cuff banter and Triumph, the Insult Comic Dog, vitriol sprayed - rather than carefully targeted -- at political opponents, fellow partisans, and journalists portended a half-life as a presidential candidate that might rival Herman Cain's 2012 presidential run. Yet, time and again, Trump has turned what would have been fatal gaffes if uttered by any other candidate into rally points for voters tired of political correctness and ready for a candidate to speak abrasively if not truthfully….Despite our bafflement, there are lessons to be learned in Trump's success. Perhaps surprisingly, many of them confirm rather than challenge what we know about campaigns and elections." [HuffPost]

TRUMP AND SANDERS LEAD IN NEW HAMPSHIRE, BUT WATCH THIS WEEK - The latest polls in New Hampshire show Donald Trump is maintaining a 20-point lead over Cruz, Rubio and Ohio Gov. Kasich, who are vying for second place. According to the HuffPost Pollster average, Kasich and Cruz are tied with 12 percent, with Rubio slightly behind at just over 10 percent. On the Democratic side, the new polls give Sanders a more than 20-point advantage over Clinton. The HuffPost Pollster average, reflecting previous surveys that show a closer race, gives Sanders a slightly smaller 17-point lead. [CNN, Franklin Pierce, UMass Lowell/7NEWS, HuffPost Republicans, HuffPost Democrats]

Watch for changes after Iowa - With only eight days between Monday’s Iowa caucuses and the New Hampshire vote, it’s highly likely that what happens in Iowa will affect the standings in New Hampshire.

WINNING ISN'T ALL THAT MATTERS - Jonathan Bernstein: “Candidates seek to beat expectations, and the press and the parties judge the results against what they thought would happen. In fact, beating expectations can matter even more than the raw results because it affects the amount and tone of the coverage candidates get….A classic example: In 1984, Gary Hart was perceived to have 'won' Iowa with 16 percent -- no one expected him to finish that strongly -- and Walter Mondale was thought to have 'lost' with 49 percent, because he failed to reach 50 percent. Hart then received so much positive publicity that he pulled a major upset in the New Hampshire primary and went on to become a serious competitor for the nomination.” [Bloomberg View]

Does winning in Iowa and New Hampshire predict the nominee? - Jennifer N. Victor: “If Trump and Sanders win Iowa and New Hampshire, 2016 may be like what Democrats experienced in 2000 and 2004, and we may see these candidates as the nominees. But that outcome is far from certain and still seems unlikely in the face of the enormous institutional obstacles they face in their own parties. It's historically unusual to observe the scenario where a candidate wins Iowa and New Hampshire but does not secure the nomination; it's therefore astonishing that we may see exactly this in both of the major parties this year....If Trump becomes the Republican nominee, it's likely to upset an already tumultuous party.” [Vox]

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MONDAY'S 'OUTLIERS' - Links to the best of news at the intersection of polling, politics and political data:

-Nate Cohn explains why the Bloomberg/Des Moines Register poll is the most highly anticipated Iowa poll. [NYT]

-Harry Enten analyzes the accuracy of Ann Selzer's polls. [538]

-Steven Shepard explains why pollsters nervously await the final outcome of the Iowa caucuses. [Politico]

-The Bloomberg/Des Moines Register poll shows little support in Iowa for a Michael Bloomberg third party run. [NYT]

-Bernie Sanders has gained surprising strength among less affluent white voters. [NYT]

-Nate Silver thinks Bernie Sanders' momentum has stalled just when it matters most in Iowa. [538]

-Americans expect Donald Trump and Hillary Clinton to win Iowa. [YouGov]

-Sixty percent of Americans have an unfavorable view of Donald Trump. [Gallup]

-Steve Koczela takes a look at where New Hampshire independent voters might swing. [NHPR]

-Nick Gass explains just why Donald Trump has baffled political scientists. [Politico]

-A Pew Research report finds Americans lack trust in the security of their personal information. [Pew]

-Margie Omero and Kristin Anderson talk to Gallup's Frank Newport about new developments in the polling industry. [The Pollsters]