Among likely Democratic primary voters in South Carolina, Clinton leads with more than double Sanders' numbers.
With the race so close in Iowa, Clinton and Sanders campaign officials agree that it will all come down to who has the better organization and ground game and how many supporters they can turn out to the caucuses throughout the state next Monday.
NBC and the Union Leader announced on Tuesday that they will host and partner on a Democratic debate on February 4, in between the two critical early state contests. "If there is a large turnout I think we win, if not I think we're going to be struggling", Sanders said, adding that he did not ask the President for his endorsement.
In an article in the New York Times, Democratic Missouri Governor Jay Nixon appeared to suggest longshot Sanders wasn't mainstream enough. Obama told Politico. "You know, that has an appeal, and I understand that".
With less than a week left until the Iowa caucuses Vermont Sen.
"The DNC has said this would be an unsanctioned debate so we would not want to jeopardize our ability to participate in future debates", Sanders' campaign manager Jeff Weaver said.
"She's extraordinarily experienced - and, you know, wicked smart and knows every policy inside and out", Obama said, unabashedly touting Clinton's readiness to be commander-in-chief.
The DNC scheduled only six debates for its 2016 candidates, and, contrary to its practice in previous election years, forbade candidates from taking part in debates not sanctioned by the party.
Sanders' visit comes as Obama has opened up about his thoughts on the race.
According to White House visitor logs, Sanders has visited the White House more than 40 times since Obama was first elected president, but the Vermont senator only met privately with him once, on December 15, 2014.
Sanders stressed that he hoped to emulate President Obama's ability to promote high turnout in the upcoming Iowa caucuses and New Hampshire primary.
On that, Sanders reiterated his opposition to the Iraq War but said he would continue the course that Obama has charted.
Sanders leads 53 to 41 percent among circusgoers who cite the economy and jobs as the most important issue, while Clinton leads 50 - 44 percent among those who list health care.
That's an obvious reference to how the Democrats haven't exactly gone out of their way to draw attention to these debates. The reality that Sanders is giving Clinton a run for her money has set in, even in the White House.