recently, officials cast Nevada as one of several safeguards in the primary calendar — part of the so-called "firewall" aides have cited for months. Clinton, they've said, will benefit from the Latino population and from Mook’s experience in the state, where he led her 2008 campaign.

During the November briefing, according to the attendee, Mook assured backers that Clinton's Nevada operation was already well ahead of her rival's. The Sanders campaign, he told them, had only just started organizing for the state’s caucuses. (One person close to the Clinton operation said she has approximately 35 staffers in Nevada headquarters. Neither campaign has publicly released a staff count.)

More recently, on a conference call with supporters, campaign officials shared internal polling that showed Clinton up as much as 25 points inNevada.

There's been no public polling there in the last two months. The last survey, conducted by Gravis Marketing the week of Christmas, put Clinton up 23 points. (A CNN poll in October, meanwhile, showed Clinton with a smaller 16-point advantage.)

The campaign has already started to add resources to the March states that follow Nevada and South Carolina. The Tuesday memo from Mook promised that Clinton would be “competing aggressively” in both states, but stressed a wider advantage in many of the 28 primaries and caucuses planned for the month of March.

“Whereas the electorates in Iowa and New Hampshire are largely rural/suburban and predominantly white,” Mook writes, “the March states better reflect the true diversity of the Democratic Party and the nation – including large populations of voters who