WASHINGTON — An insurgent liberal hero is once again rising in Iowa, drawing huge crowds of young supporters and making Hillary Clinton’s team see ghosts of her 2008 caucus collapse.

Vermont Sen. Bernie Sanders has clawed his way into a virtual tie with Clinton in Iowa polls, and the former secretary of state's backers are increasingly nervous that she could lose there once again.

"I still have 2008 PTSD, and I’m feeling a lot of it right now," said one Iowa Clinton loyalist who has been involved in both campaigns. "These polls have closed up. His fervent support is not something she’s matching… Things seem to be a little off the rails."

Recent polling has found a coin-flip race with less than three weeks to go. The gold standard of Iowa polling, the Des Moines Register/Bloomberg poll conducted by Ann Selzer, found Clinton leading by just two points in results released Thursday morning.

New Bloomberg/Des Moines Register poll in Iowa: Clinton 42% Sanders 40% O'Malley 4% Uncommitted 14% https://t.co/tjckLJ60ax — Dan Merica (@danmericaCNN) January 14, 2016

Eighteen days out from the Iowa caucuses in 2008, Clinton held a four-point lead over Obama. A few days after that, Selzer’s poll found Clinton up by 7.

The Hawkeye State is the first to cast its ballots for president. It can give underdogs a huge boost toward their party’s nomination — like it did for then-candidate Obama in 2008 — or put a front-runner’s campaign on the skids, like it did to Clinton.

While Clinton’s allies think she’s in better shape to bounce back later in later primary states if she can’t get past her Iowa problems, they disagree over what if anything she can do to end her recent struggles. A few want her to lean harder into policy contrasts like her recent attacks on Sanders over gun control, while others said she needed to highlight her biography more and soften her image. Some advised Clinton to ditch the smaller events she’s been holding and do more big rallies to match Sanders’s energy — a tactic she tried last time around. Others said she needed to spend more time one-on-one with Iowa caucus-goers.

"She’s not doing the big rallies because she can’t get the big crowds,” said the Iowa Clinton ally. "Maybe people are too anxious over this, and that anxiety is spilling over into cautiousness and overthinking decisions. Everyone’s on edge given how much we’ve invested in Iowa."

Sanders has a fervent following of millennial voters and is closing in on Clinton in the state, much as Obama did eight years ago. Clinton’s team is spending big to try to keep her ahead, touting her experience and arguing she’s the most electable candidate while attacking his healthcare plans. As then-Sen. Barack Obama channelled Democrats’ fury over the war in Iraq and lust for change, Sanders has captured the current liberal zeitgeist with his tirades against income inequality.

So much that’s happening between Clinton and Bernie Sanders today echoes back to her losing battle against Obama in Iowa.

"I have a buddy who was with Obama last time who has been sending around links to recent stories and polling data that read the exact same as at this point in 2007 and 2008," said John Davis, a Clinton backer who was former Rep. Bruce Braley’s (D-Iowa) chief of staff.

Clinton’s reaction to the tightening race has echoes of the 2008 as well — and some Clinton backers fret that she’s repeating some of her past mistakes, leaning too hard on an electability and experience argument.

Clinton released a new ad Wednesday evening saying she’s "always stood strong to get the job done" that was heavy on archival footage from the ‘90s. Just days ago, another spot called her "tested and tough" and argued she’s the "one candidate who can stop" the GOP.

For some Clinton backers, the ads caused flashbacks.

"It wouldn’t surprise me at all if it turns out Mark Penn is back in the game, right down to some of the selection of the footage," one 2008 alum said of Clinton’s polarizing chief strategist and ad-maker from the last campaign. "That doesn’t exactly have 2016 written on it. Those were some really interesting stock footage choices."

Sources close to Clinton’s campaign laughingly dismissed the idea that the controversial Penn could be back in the fold.

On Tuesday, Clinton attacked Sanders for thinking he could “wave a magic wand” and do what he wanted as president. The words mirrored her February 2008 barb at Obama that “You are not going to wave a magic wand and have the special interests disappear.”

Chelsea Clinton followed up with an attack on Sanders’s healthcare plan, saying it would “dismantle” Obamacare — not too far from her attacks on Obama’s 2008 healthcare plan.

Clinton’s campaign doubled down on that attack Wednesday, slamming Sanders's campaign for refusing to say how he’d pay for his plan to expand Medicare to everyone and accusing him of planning to pay for it by raising middle-class taxes.

"To Bernie Sanders with thanks for your commitment to real health care access for all Americans..."-@HillaryClinton pic.twitter.com/XMVPEx8fT8 — Bernie Sanders (@BernieSanders) January 13, 2016

Sanders’s campaign fired back by sending around a signed photo of the two politicians Clinton had sent to him in 1993.

"To Bernie Sanders, with thanks for your commitment to real health care access for all Americans and best wishes," the then-first lady wrote to the then-congressman.

Not everything is the same this time around.

Clinton’s team has been able to lob effective attacks on Sanders’s gun record, the one area where she’s clearly to his left, and has locked down nearly the entire Democratic establishment behind her campaign. Obama had much more establishment support, a much shorter record, and no such policy weaknesses in 2008.

Sanders is significantly to the left of Obama on many issues, and his embrace of the “Democratic socialist” title may give Democratic voters more pause about electability than the fresh-faced Illinois senator gave them eight years ago.

Obama was able to use his Iowa win to show black voters he was electable, and they flocked to him in record numbers, helping him win South Carolina and a number of other states. Clinton’s team thinks she has a much stronger appeal to African-Americans than Sanders.

And Clinton has invested more heavily in her field operation — and made more trips to Iowa — after facing attacks that she dismissed the state eight years ago.

"I don’t think it feels anything like '08. The Clinton team was never really confident in Iowa. If anything it’s the opposite. People thought last time that Hillary didn’t take Iowa seriously," said Clinton ally Hilary Rosen.

How the Democratic race in Iowa has tightened over time in @bpolitics/@DMRegister poll https://t.co/HZuAlHq1KL pic.twitter.com/OSsCnTIYWm — Jennifer Epstein (@jeneps) January 14, 2016

But unlike in 2008, Clinton actually trails in New Hampshire polling with less than a month until the first-in-the-nation primary.

"While we know it’s going to go down to the wire in both places, I think we’re confident in the ground game that we’ve built both in Iowa and New Hampshire," Clinton spokesman Brian Fallon said during a Wednesday conference call.

Clinton’s team is confident that even if she loses both states she can still win the nomination. But her allies admit her grip on Iowa is tenuous. And they're hoping history doesn't repeat itself.

"It is a true fight. Both have deep statewide organizations," said Brad Anderson, a top Obama Iowa veteran who’s now helping Clinton’s campaign. "I think it’s a coin-flip."