Deep breaths. Deeeeeep breaths. Could Joe Biden lose his grip on the Democratic presidential nomination not to a younger and more charismatic challenger, but to an older socialist crank? A new NBC/Wall Street Journal poll shows Bernie Sanders taking a slight lead over the presumed frontrunner 27/26 with just days to go before the first caucus of the primaries:

Just days before the first votes are counted in the Democratic primary, a new NBC News/Wall Street Journal national poll finds Vermont Sen. Bernie Sanders and former Vice President Joe Biden statistically tied at the top of the Democratic field.

Sanders gets 27 percent support from Democratic primary voters around the country, while Biden gets 26 percent. Sanders’ single-point advantage, while well within the poll’s +/- 4.74 percentage point margin of error, marks his first lead of the primary in the NBC/WSJ survey.

Massachusetts Sen. Elizabeth Warren is the only other Democrat registering in double digits, at 15 percent, while former New York City mayor Michael Bloomberg now holds the fourth place spot, at 9 percent. Former South Bend mayor Pete Buttigieg gets 7 percent support in the poll; Minnesota Sen. Amy Klobuchar has 5 percent, and businessman Andrew Yang stands at 4 percent. No other candidate has 3 percent support or more.

It’s the highest rating Sanders has received in this polling series. A month earlier, he trailed Biden 21/28, with Elizabeth Warren hot on his heels at 18%. In this poll, Sanders has picked up six points, Warren has lost three, and Biden slid two points — the latter two within the margin of error, but not Sanders. It’s Biden’s worst showing since July, when Sanders was only at 13% and Warren had 19%. Interestingly, though, Sanders comes in third for voters’ second choice at 15%, with Warren (24%) and Biden (20%) well ahead. The Sanders boom looks like strictly a product of ardent supporters, not necessarily less passionate voters.

Two other moves of note in this latest iteration involve potential insurgent candidates. Despite getting a lot of media attention, Pete Buttigieg hasn’t moved much at all in this series since July, when he also got 7%. In December that ticked up to 9%, but he’s back at his rather consistent level. Michael Bloomberg, on the other hand, went from 4% last month to 9% now, vaulting into fourth place on the back of a massive national ad buy that will roll into the Super Bowl on Sunday. Bloomberg might actually qualify for the next debate.

How serious is the Sanders boom? The RealClearPolitics aggregate tracking shows it’s not just a product of this series, but it’s also still somewhat limited:

Biden’s support isn’t dropping; Sanders appears to be consolidating more of the Not-Biden vote, at least lately. Warren and Buttigieg are fading on a roughly similar trajectory as Sander’s rise. One has to wonder if Sanders might be going up even more if Bloomberg hadn’t jumped into the race to split the Not-Biden vote even further.

What happens in Iowa next week and New Hampshire after that might not impact this much, either, except to cull out the pretenders. Iowa’s close enough that both Biden and Sanders will end up with decent delegate counts, and all Biden needs to do is finish second in New Hampshire to keep from getting embarrassed. A win in Nevada and a blowout in South Carolina will spell the end of the Sanders’ boom, if Democrats’ Bernie Panic doesn’t do the job first. Deep breaths, DNC, deeeeeeep breaths ….