Former president Bill Clinton criticized Democratic presidential candidate Bernie Sanders at a campaign rally in Milford, N.H. Feb. 7, fighting back against criticism of Hillary Clinton's ties to Wall Street. (Reuters)

For weeks, former president Bill Clinton has been the doomsday device of Hillary Clinton’s presidential campaign — a mighty weapon capable of doing great good or harm to her campaign — and held in reserve until absolutely needed.

Now, as Hillary Clinton — who barely won the Iowa caucuses last week — seeks to seize momentum from Sen. Bernie Sanders of Vermont in his own back yard, days before the New Hampshire primary, that moment of truth has come. The former president, uncharacteristically quiet in recent weeks even as Republican contender Donald Trump called him “an abuser,” lashed out at Sanders on Sunday, according to reports from Bloomberg Politics, Politico and the New York Times, while campaigning for his wife in New Hampshire, leveling charges that the senator is hypocritical and that some of his followers are sexist.

The former president appeared to get the most mileage out of his criticism of “Bernie Bros” — the name given to some supposed young male supporters of the senator. Bill Clinton did not use the term — but he offered quite the critique. As Politico noted, Clinton accused these people, some of whom have been denounced by Sanders, of sexist behavior online.

“People who have gone online to defend Hillary, to explain why they supported her, have been subject to vicious trolling and attacks that are literally too profane often, not to mention sexist, to repeat,” Clinton said, according to the Times.

Hillary Clinton's New Hampshire campaigners are making a ground-game push, hoping to keep Clinton within striking distance of heavily favored Bernie Sanders in the final days before the Democratic primary there. (Dalton Bennett/The Washington Post)

The former president also accused Sanders of selling pipe dreams to supporters — a barbed version of Hillary Clinton’s observation, during last week’s debate, that “progressives make progress.”

“When you’re making a revolution, you can’t be too careful with the facts,” he said.

Bill Clinton spoke to a number of proposals he said Sanders hadn’t adequately explained. He hit Sanders on his single-payer health-care plan: “Is it good for America? I don’t think so. Is it good for New Hampshire? I don’t think so. The New Hampshire I knew would not have voted for me if I had done that.”

The former president noted a CNN report that said Sanders, despite his constant criticism of Wall Street, had taken money from wealthy donors: “Anybody who takes money from Goldman Sachs couldn’t possibly be president…. He may have to tweak that answer a little bit, or we may have to get a write-in candidate.” The former president said he “fell out of his chair” when he read the CNN story.

As Bloomberg Politics noted, Bill Clinton criticized Sanders for making unfair use of a Democratic National Committee data breach: “It was your campaign that made 25 separate inquiries in the mere space of 30 minutes trying to breach information out of computers…. In private [the Sanders campaign] sent an email complaining [about the Democratic National Committee] leaving the keys in the car, and said, ‘All I did was drive off.’”

Bill Clinton also noted that, in 2000, Sanders voted for the Commodity Futures Modernization Act, which helped deregulate Wall Street. Hillary Clinton’s “opponent, a champion of all things small, an enemy of all things big, voted for that bill,” he said of Sanders. “But you will never hear her say that he is the tool of Wall Street because of that.” (As president, Clinton, of course, signed that bill into law.)

The Sanders campaign criticized the former president’s rhetoric — characterized by the New York Times as “an escalation.”

“It’s unfortunate that President Clinton is choosing to engage in the kind of negative attacks that he is on the eve of the New Hampshire primary,” Jeff Weaver, Sanders’s campaign manager, told Bloomberg Politics. “Clearly this is a sign that the Clinton campaign is very concerned about the state of the race and the fact that recent national polls have shown that this is really a race that is down to one or two percentage points difference.”

Although The Washington Post’s Philip Bump has suggested some skepticism of a recent national poll showing a two-point race between Sanders and Hillary Clinton, the stakes could not be higher in New Hampshire. Sanders is leading polls in the state, and a win in the Granite State is a matter of pride for the former first family. Bill Clinton was labeled the “Comeback Kid” in the media after he finished an unexpectedly strong second place in New Hampshire in 1992; he went on, of course, to win the nomination and the general election. And although Hillary Clinton lost the 2008 nomination battle to Barack Obama, her win in New Hampshire that year seized some momentum from the junior senator from Illinois who had won a decisive victory in the 2008 Iowa caucuses shortly beforehand.

If Clinton loses to Sanders despite her husband’s attacks, the battle for the nomination may get only harder. Next up is Nevada and then South Carolina, where Hillary Clinton may be relying on minority voters to help her beat Sanders — but, then again, Bill Clinton’s perceived racism hurt his wife’s attempts to win South Carolina in 2008 when he called Obama’s candidacy “the biggest fairy tale I’ve ever seen.” The former president later said he was only pointing out that Obama, as senator, voted against the Iraq War, but then voted to fund it.

“So ‘that story is a fairy tale’ — now, that doesn’t have anything to do with my respect for him as a person or as a political figure in this campaign,” Clinton told the Rev. Al Sharpton at the time. “He’s put together a great campaign. It’s clearly not a fairy tale. It’s real.”