Ames, Iowa CNN  — 

Hillary Clinton is turning her stump speech into a near constant attack on Vermont Sen. Bernie Sanders as she suddenly faces the threat of losing the first two early-voting states next month.

Two polls released Tuesday find Sanders with leads in both Iowa and New Hampshire, a surge that has Clinton aides worried.

Clinton compared her stance with Sanders on guns, health care and Wall Street. Since the first Democratic debate in October, Clinton has used different issues to knock Sanders. But on Tuesday, her speech was different, with more sustained and focused knocks on the unlikely front-runner in Iowa and New Hampshire.

Clinton hit Sanders for bragging about standing up to special interests, but siding with the National Rifle Association on certain legislation. If Sanders is to tout his willingness to stand up to special interests, Clinton said at her events that Sanders should “stand up to the most powerful special interest, stand up to that gun lobby.”

Clinton then turned to Wall Street, an issue Sanders has tried to use against Clinton by casting her as too close with the nation’s biggest banks. “Don’t talk to me about standing up to corporate interests and big powers,” Clinton said to Sanders. “I’ve got the scars to show for it and I am proud of every single one of them.”

Clinton is in a strong position in many of the states that hold primaries later in the nominating contest. But a loss in the Iowa caucuses on February 1 will revive memories of Clinton’s third-place finish there in 2008, which ultimately doomed her first presidential bid. New Hampshire, which rewarded Clinton in 2008 and her husband, Bill, in 1992, is even tougher for her this year since she’s up against a popular senator from neighboring Vermont.

Adding to Clinton’s troubles is an interview Vice President Joe Biden gave CNN on Monday in which he praised Sanders and suggested the former secretary of state was new to addressing income inequality.

“It’s relatively new for Hillary to talk about that,” Biden told CNN’s Gloria Borger, saying that Clinton has “come forward with some really thoughtful approaches to deal with the issue” of income inequality.

In response to the tightening race, Clinton is dispatching two of her best-known surrogates – husband Bill and daughter Chelsea Clinton – onto the campaign trail. Bill Clinton has already visited New Hampshire and Iowa and will return to the Granite State on Wednesday; Chelsea Clinton was there Tuesday.

The former first daughter even went after Sanders in the Granite State, charging that his healthcare plan would give too much power to Republican governors.

“I don’t want to live in a country with unequal health insurance,” Chelsea Clinton said. “I don’t want to empower Republican governors. And I think that is what Senator Sanders wants to do.”

At her event here on Tuesday, Hillary Clinton zeroed in on Sanders’ proposal to pass a single-payer health care plan without raising taxes on the middle class.

“There is no way that can be paid for without raising taxes on the middle class, the arithmetic just doesn’t add up,” she said.

All of this culminated in Clinton using Sanders’ oft used line – that he is taking launching a political revolution - against him.

“If that is the kind of revolution he is talking about, I am worried folks,” she said to applause.

The reason behind the focus on Sanders is two-fold: The Iowa caucuses are less than a month a way and many voters in the audience said they were attending the event to make up their mind, a fact Clinton acknowledged from the stage.

But they are also because Clinton and he aides see the race tightening.

A new Quinnipiac University poll released Tuesday shows that Sanders is now the front-runner in Iowa – with 49% support to Clinton’s 44% and former Maryland Gov. Martin O’Malley’s 4%.

Clinton aides have long said they expected the race to tighten but there is concern inside Clinton’s campaign that Sanders is catching fire in the important weeks leading up to the caucuses.

The near total focus on Sanders is new for Clinton, a candidate who spent the early months of the campaign avoiding even mentioning Sanders’ name.

Tuesday’s event, where Clinton also accepted the endorsement of the Brady Campaign to Prevent Gun Violence, amplified a trend of Clinton attacks that Sanders said at the Iowa Brown and Black Forum on Monday night that he’s noticed.

“It could be that the inevitable candidate for the Democratic nomination may not be so inevitable today,” he said.

That Sanders now has a shot at winning the first two states in the Democratic nominating process is in part a reflection of their makeup: Iowa and New Hampshire are whiter and more liberal than the broader party electorate.

The bigger test would come as the campaign shifts to Nevada and South Carolina – where Democrats will have their last debate Sunday night in Charleston before the voting begins in Iowa on February 1.

She is also campaigning with high-profile surrogates – including the heads of Planned Parenthood and the Brady Campaign, highlighting her support on women’s health issues and gun control, as well as Transportation Secretary Anthony Foxx, who underscores Clinton’s ties to President Barack Obama’s administration.

Sanders aides attribute some of their lead in Iowa to the fact that although the Vermont senator went on air with his first ad last in 2015, he is currently airing more ads in the state than Clinton, according to CMAG/Kantar Media.

Clinton aides believe that count is slightly misleading, largely because it does not include cable ads, which Clinton has invested heavily on. What’s more, Clinton aides are confident that their concentrated ads in Cedar Rapids and the Quad Cities area of Iowa will pay off more than Sanders’ ads in areas Sioux City and Omaha, more conservative areas of the state.