It seems that supporters of Democratic presidential candidate Bernie Sanders have given their response to Hillary Clinton's newest line of attack. The Sanders team reports that his campaign pulled in about $1.4 million in just 24 hours, nearly quadrupling their daily average.

“Thanks, Team Clinton,” says Michael Briggs, spokesman for the Sanders campaign.

The surge in contributions comes in the wake of interviews and speeches by Mrs. Clinton in which she questioned his electability in a general election against a Republican opponent and called attention to his vote for a 2005 bill that shielded gun manufacturers from liability lawsuits.

Even her daughter, Chelsea Clinton, has stepped into the fray, charging that Sanders wants to “dismantle” Obamacare and Medicare. For the record, Sanders proposes a single-payer health care plan, but has yet to offer details on how he would fund it.

Mrs. Clinton likely stepped up her attacks after seeing the latest poll numbers coming out of Iowa and New Hampshire. A Monmouth University Poll has Clinton trailing Sanders in New Hampshire by 14 points, with 39 percent to his 53, while the Des Moines Register shows the double-digit lead she had in Iowa a month ago shrinking to just two points.

On the national level, the latest polls paint a race that is tightening by the day.

It is hard to imagine that eight years ago a candidate as far removed from the party establishment as Bernie Sanders would have broken out of the single digits in national polling, much less offered a serious challenge to the party's front-runner. Sanders' clashes with the Democratic National Committee -- from the inconvenient weekend scheduling of the debates to temporarily cutting off access to the DNC's voter database -- have done little to blunt his support.

In fact, they may be helping him.

Though their policy proposals couldn't be more different, Sanders' rise mirrors Donald Trump's unexpected success in courting the Republican base. Both candidates have found their voices by pitting themselves as the underdogs battling the elites in their respective parties in addition to the other side -- an ironic twist on the “triangulation” strategy that Bill Clinton used in his re-election campaign in 1996.

Even if November ends with a President-elect Clinton or Rubio, 2016 is already looking to be the year of the outsider.

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