Bernie Sanders is surging in the polls and putting presumed nominee Hillary Clinton on her heels, but the Vermont Senator may still have another huge move coming up that could tip the scales this primary season.

After Clinton held off a late-summer surge from Bernie Sanders and started to pull away through the fall, it began to look as if the race for the Democratic nomination might be out of reach. Clinton was regularly topping 50 percent support in national polls and widening her lead in Iowa, the key early state where she faltered in 2008.

But, the last week or so has brought a dramatic change, with Bernie Sanders surging even faster than Obama in 2008 when he pulled off a similarly surprising upset of Clinton. A new Des Moines Register/Bloomberg poll released Thursday morning shows Bernie Sanders within the margin of error, trailing Hillary Clinton by just two percentage points, 42-40. Just one month ago, Clinton held a 48 percent to 39 percent lead in that same poll.

As pollsters have noted, Bernie Sanders is now gaining ground on Hillary Clinton faster than Obama did in 2008, when the then-Illinois Senator also erased a large deficit. Sanders actually has a better standing in Iowa now than Obama did in late 2007, just before voting started.

Like Obama, Bernie Sanders has some huge support among younger voters, the poll read as follows.

“Among those younger than 45, Sanders bests Clinton 59 percent to 27 percent. And among those who say they plan to attend their first caucus, he leads 52 percent to 34 percent.” “Clinton wins with older Democrats (56 percent to 26 percent) and women (49 percent to 32 percent).”

Bernie Sanders also appears to be planning a move on one of Clinton’s key demographics: black voters. Sanders has struggled among this group, which will be key throughout the primary season, especially as the vote heads south for a key stretch after the initial few states.

Sanders is trying to raise his numbers with events at historically black colleges and universities. He is scheduled to appear at a number of colleges across the south, including Tennessee State University in Nashville; Alabama State University in Montgomery; Jackson State University; Florida A&M University in Tallahassee; Virginia State University in Petersburg; and Howard University in Washington, D.C.

Sanders has a way to go among this group. A November 2015 Winthrop poll showed found that about 80 percent of South Carolina’s black voters supported Clinton. But, Sanders has sharpened his focus on getting black voters, scheduling more appearances and seeking out some key endorsements.

He’s also taken to social media to reach younger black voters. Last year, he teamed up with Atlanta rapper Killer Mike for a six-part video interview, talking about issues ranging from gun control to Sanders’ support of Democratic socialism.

As USA Today noted, Killer Mike is lending his endorsement to Sanders.

“After spending five hours with someone who has spent the last 50 years radically fighting for your rights and mine, I can tell you that am very proud tonight to announce the next president of the United States, Sen. Bernie Sanders.”

It may be tough to combat Clinton’s endorsements. She has support from Eric Holder, the nation’s first black attorney general, which some see as a proxy endorsement from President Obama himself.

“It’s a very key endorsement for Secretary Clinton. He was the most visible black cabinet member of Obama’s administration,” said Steven Taylor, a professor of government at American University in Washington, D.C., in an interview with Reuters. “Even though Obama hasn’t made an endorsement, the public will see this as a proxy endorsement.”

With the margin between the two candidates growing smaller and smaller each day, it may not take much to put him over the top. Experts say that if Bernie Sanders can capture even a bit more of the black vote, it could tip the polls in his favor for good.

[Photo by Mark Wilson/Getty Images]