LONDONBERRY, N.H. (AP) — On the rise in a tightening race, Marco Rubio shouldered intensifying attacks Friday from moderate-leaning Republicans who fear a strong Rubio showing in Tuesday's New Hampshire primary could spell the end for their frazzled presidential campaigns.

Jeb Bush and Chris Christie both accused Rubio of a lackluster set of accomplishments. Bush, campaigning with his mother, former first lady Barbara Bush, summed up the Florida senator's achievements in one word: "Nothing."

On the Democratic side, the gloves were off in a campaign that had shown more signs of comity than rancor — until now. A day after jousting in a feisty debate, Hillary Clinton struggled to defend herself against Bernie Sanders' insinuations that she's beholden to Wall Street, while Sanders faced fresh doubts about his experience on foreign policy.

As candidates crisscrossed the state, a burst of soggy snow became the latest obstacle to winning support among undecided voters. The winter surprise sidelined Donald Trump and Sanders, who canceled afternoon events as campaigns sent plucky volunteers trudging through the slush to knock on doors.

Blizzard notwithstanding, the all-out push for votes illustrated the growing stakes for Tuesday's vote. New polls showed Rubio on the rise both in New Hampshire and nationally, raising his hopes that a second-place finish Tuesday will spur Republican Party leaders to unite behind him in a bid to defeat the two polarizing front-runners: Trump and Texas Sen. Ted Cruz.

"Marco is a talented politician," Bush said on MSNBC. "He's a great guy, but he's not a leader."

His campaign released a new TV ad showing former Sen. Rick Santorum, who has endorsed Rubio, stumbling in an interview to name one Rubio accomplishment.

Rubio did pick up another endorsement from a fallen rival — former Louisiana Gov. Bobby Jindal, who dropped out of the race in November.

Cruz, the victor in last week's Iowa caucuses, was struggling to put complaints about his campaign's tactics in the rearview mirror, as new evidence emerged of what challenger Ben Carson has dubbed "dirty tricks." Carson told a Fox News podcast that Cruz's lackadaisical defense brought to mind Clinton's response to the attacks in Benghazi, Libya.

"I'm not saying that it rises to the level of Benghazi, I'm saying it's the same kind of attitude," Carson said. "The attitude being: It's water under the bridge."

Fueling the dust-up were rumors spread by Cruz's campaign hours before the Iowa caucuses about Carson dropping out of the race. Trump has also cried foul, arguing Cruz "stole" the election by peeling off Carson supporters to surge past Trump.

Cruz has apologized for circulating the rumor based on a news report about Carson traveling to Florida after the Iowa voting. But a string of further revelations has kept the controversy alive, including a Cruz campaign mailer resembling an official "voting violation" notice to Iowans. The latest wrinkle came via a pair of voicemails obtained by Breitbart News, purportedly from Cruz's campaign, telling Iowans to caucus for Cruz because Carson was suspending his campaign.

"By the way, if you get a call on Tuesday night that I dropped out, it isn't true," Rubio said, tweaking Cruz during a town hall in Derry. "Keep voting."

Christie — who, like Bush and John Kasich, has it all on the line in New Hampshire — offered dire predictions about the state's first-in-the-nation primary if voters side with Cruz, Trump or Rubio, a trio that Christie suggested had ignored the Granite State.

"If you reward those folks who don't show up here, there is no reason for New Hampshire to be first," Christie told a town hall meeting in Dover.

For Clinton, who revived her campaign here in 2008 after a bruising Iowa loss, the final sprint in New Hampshire offered an unpleasant reckoning with reality: Once again, the former first lady is locked in a bona fide contest for a nomination most Democrats had thought was hers for the taking. A Boston Globe/Suffolk University poll released Friday showed Clinton narrowing Sanders' lead in New Hampshire, though the two are running neck-and-neck nationally.

Sanders and Clinton tussled aggressively in their first one-on-one debate Thursday, with Clinton accusing the Vermont independent of an "artful smear" for suggesting her speaking fees and donations from Wall Street firms bound her to corporate interests. Sanders countered that Clinton "does represent the establishment."

Casting ahead to the Nevada caucuses in two weeks, Clinton launched her first campaign ads in Spanish, a TV and radio spot highlighting her advocacy on immigration, health care and education. Meanwhile, her campaign tried to flip the script on Sanders by arguing Clinton represents the opposite of an establishment contender.

"When folks talk about a revolution, the revolution is electing the first woman president of the United States," said Sen. Debbie Stabenow, D-Mich., as she joined Clinton on the campaign trail in Manchester.

But Sanders was sticking to core messages in the final days before the primary: government-run health care, free tuition at public universities and an end to gigantic, all-powerful financial institutions.

"I want to see banking become boring again," Sanders said. "Remember boring banking?"

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Lederman reported from Washington. Associated Press writers Kathleen Ronayne in Dover, Lisa Lerer in Manchester and Sergio Bustos in Concord contributed to this report.

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Reach Josh Lederman on Twitter at http://twitter.com/joshledermanAP