A Des Moines Register and Bloomberg News poll of likely Democratic caucus-goers showed Vermont Senator Bernie Sanders just seven points behind former Secretary of State Hillary Clinton.
Clinton received 37 percent support, Sanders took 30 percent support, and Vice President Joe Biden, who has not entered the race, received 14 percent support of Democrats polled. The results marked the first time support for Clinton dipped below 50 percent in the poll, NBC News reported.
For Sanders, the Iowa data also showed the self-described Democratic Socialist is polling particularly well with first-time caucus-goers. Support for Sanders increased from 16 percent in the poll three months ago.
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"The people who were not taking [Sanders] very seriously three months ago were not people in Vermont," said Bill Grover, a political scientist at St. Michael's College in Colchester, Vermont. "Those were people outside, who perhaps didn't know about him."
Grover attributed Sanders' surge in Iowa to an aggressive public campaign schedule that has helped him introduce himself to the nation and combat a name recognition problem.
At each of his rallies, Sanders reiterates his core, populist message that the economic and political systems in this country are broken: that Wall Street and billionaires are too powerful, he tells his large and enthusiastic audiences, and that millions of hardworking American families are getting left behind.
"It makes no sense to me to give tax breaks to billionaires and have so many of our kids living in poverty," Sanders told Andrea Mitchell of MSNBC on Monday in a live interview, as one example of a message that seems to be connecting well with supporters.
Grover told necn Sanders does have to continue his outreach to minority voters in a big way, and noted Sanders will surely face an uphill climb come "Super Tuesday." On Tuesday, March 1, 11 states will vote, and the Clinton campaign will have much more money to spend on advertising than the Sanders camp.
"When you have to get your field organization spread out around the whole country, and contest primaries simultaneously on the same day, that becomes a little bit trickier, I think, in terms of money," Grover added. "Money doesn't always win, but it certainly helps a lot."
Elaine Young, a professor of digital and social media marketing at Champlain College, said Sanders' growing social media reach echoes the Iowa poll: as more people around the country hear from him, they're sharing his messages online, and Young said that can help strengthen his base of support.
"His social media content is picking up at the same time his popularity is picking up," Young said of Sanders. "He is energizing people first in-person, then they're going to their social networks and sharing that energy. Without the in-person enthusiasm, there wouldn't be enthusiasm on social networks."
On the Republican side, the same Iowa polling showed encouraging news for the campaigns of billionaire business mogul Donald Trump and retired neurosurgeon Ben Carson. Trump led the large Republican field in the poll, enjoying 23 percent support. Carson received 18 percent.
Both Trump and Carson significantly improved their support and favorability ratings over the past three months, according to the poll data. Political observers have said their "political outsider" status has connected with many voters who are looking for something different from Washington.
Sanders will return to Iowa on Thursday of this week, kicking off a swing with stops in Grinnell, Ottumwa, Burlington, Muscatine, the Meskwaki Tribal Center in Tama and Cedar Rapids, according to his campaign.
This weekend, the Sanders campaign issued a statement on the Iowa poll results:
“What this new poll shows is that the more Iowans get to know Bernie the better they like him and what he stands for. We’ve seen the same thing in New Hampshire and across the country,” campaign spokesman Michael Briggs said. “At a time when the middle class continues to disappear and almost all new wealth and income is going to the top 1 percent, the American people want leadership that is prepared to fight for working families and take on the greed of a billionaire class that has enormous control over our economy, our political life and the media.”