Last week, on the heels of his landslide win in the New Hampshire Democratic presidential primary, Sen. Bernie Sanders of Vermont started appearing on TVs in four new March 1 states. Two of them -- Colorado and Minnesota -- are holding caucuses and had gone for Barack Obama over Hillary Clinton in 2008. One of them, Massachusetts, shares a border with Vermont and New Hampshire.

And then there is Oklahoma.

The Sooner State was targeted with an even bigger ad buy than Massachusetts (roughly $400,000, compared to $300,000), which surprised some Democrats. In the 2008 Oklahoma primary, Clinton thumped Obama by 23.6 points, her biggest Super Tuesday victory outside Arkansas. The shrunken Oklahoma Democratic establishment was fully behind her this time. She had rallied and raised money here, and Sanders had not.

Yet Oklahoma could be a proving ground for a particular kind of Sanders voter -- the white, working-class Democrat who feels abandoned by the national party. Grassroots enthusiasm for Sanders has been building for months. (It was Oklahoma, not Vermont, that midwifed Feel the Bern Salsa.) Sanders's pitch to Oklahoma is roughly what it was in New Hampshire, pure populism.

"If he’s been here for Oklahoma for an event, I’ve missed it, but he does some awfully good ads," said David Walters, a former Democratic governor of Oklahoma who has endorsed Clinton. "They’re dynamite ads. His media folks are just spectacular. I don't know who's doing them, but I suspect they're old Clinton folks."

Polling had shown steady progress for Sanders even before the ad buy. The Sooner Poll, the most respected in the state, found Clinton up over Sanders by 46.6 percent to 12.2 percent in November. The latest edition of that poll found Clinton up by just 16 points -- her support was flat, while undecided voters were going to Sanders. Even if those numbers held, Clinton would fall short of her 2008 margin, and Sanders would gain delegates. (A Public Policy Polling survey released Wednesday found a two-point race, and while Democrats don't take that poll as seriously, they recognize the movement.)

Several factors are cutting against Clinton. One: Oklahoma, like many red states, has seen the Democratic party diminish under President Obama. In 2008, when Clinton won the primary, Democrats held a 10-point party registration advantage over Republicans. Last year, after years of growth and election wins, the number of registered Republicans surpassed the number of registered Democrats. For the first time in Oklahoma's 108 years of statehood, the Democrats were in the minority. And the ones who had bolted were more often conservatives, the people who had gone for Clinton in 2008.

Second, this year's Oklahoma primary will be open to independents for the first time ever. Republicans will hold a closed primary. The message-sending independent voter, whose existence was definitely confirmed in New Hampshire, may come out for Sanders.

Third -- and there is no good way to put this -- Sanders is white. In 2008, Oklahoma was one of the first states where the Obama campaign saw a significant fall-off with white working-class Democrats, uncomfortable with a black nominee. Former senator John Edwards (N.C.), who had quit the race (but not yet been exposed as a philanderer), pulled more than 10 percent of the primary vote, cracking 20 percent in some counties, and actually beating Obama in Pushmataha, Roger Mills and Ellis counties. In 2012, with no serious primary opponent, Obama lost all three of those counties and nine more.

"When they called me and congratulated me on winning the state for Hillary," recalled Walters, "I said, thanks, but let's be honest -- Obama was a Canadian. That was our euphemism for him being African American in a conservative state."

Sanders has done nothing to separate himself with Obama, but there's an expectation that he can win some voters who never considered supporting the president. His message might gain more traction among Democrats who've watched a Republican governor and legislature respond to the crash in oil prices with a series of budget cuts.

If the message does land, there'll be some precedent. Sanders famously (or infamously) keeps an image of Eugene Debs, the perpetual Socialist Party candidate for president, in his Senate office. Debs never ran better than the 1912 campaign, and Oklahoma was his second-best state, with 16.4 percent of voters pulling the Socialist lever. Debs did better in just one other state, Nevada -- which, of course, holds a Democratic caucus on Saturday.

This year, the day after Nevada's vote, Bill Clinton is heading to Oklahoma for a fundraiser.