COLUMBUS, Ohio (Reuters) - For long-shot moderates trying to compete for the Democratic presidential nomination, this week’s debate in Ohio marked a significant shift in strategy.

FILE PHOTO: U.S. Senator Amy Klobuchar, South Bend Mayor Pete Buttigieg, U.S. Senator Bernie Sanders and U.S. Senator Elizabeth Warren (L-R) greet each other on the first night of the second 2020 Democratic U.S. presidential debate in Detroit, Michigan, U.S., July 30, 2019. REUTERS/Lucas Jackson/File Photo

Attacking former Vice President Joe Biden, the longtime front-runner in the race, was out. Going after U.S. Senator Elizabeth Warren, the candidate who has grabbed the momentum in the nominating contest, was in.

It might have seemed counter-intuitive for Democratic moderates such as Pete Buttigieg, the mayor of South Bend, Indiana, and Amy Klobuchar, a U.S. senator from Minnesota, to direct their fire at Warren. She is a progressive who champions sweeping structural change. Biden is an establishment favorite who appeals to the same kinds of voters the lower-tier rivals are chasing.

But campaign sources said the approach reflected a new dynamic in the race. With Warren’s ascent in the polls, Buttigieg, Klobuchar and other moderate candidates are trying to slow Warren’s rise while also positioning themselves to benefit should Biden falter.

Part of that strategy has involved warning moderate voters that Warren’s ambitious plans for universal healthcare coverage and free public college may be unworkable legislatively and unpalatable to a large swath of the electorate.

“They are creating a third lane of sorts. There’s voters who don’t like Warren’s progressive brand of politics and want an alternative to Biden, and that’s what they are trying to provide,” said Aaron Pickrell, who ran former President Barack Obama’s Ohio campaign.

Time is running out for many of the candidates in the sprawling presidential field to make an impact. Democrats cast votes in the first nominating contest in Iowa in less than four months. The nominee will challenge Republican President Donald Trump in the November 2020 election.

For much of the year, moderate Democrats in the field have been waiting for Biden, who served two terms as Obama’s vice president, to come back to the pack. But that has largely not happened, forcing a retooling that came into sharp focus during Tuesday’s debate.

“Folks have stopped relying on the strategy that the path to success comes from stealing Biden voters and waiting for him to fall,” a campaign adviser to former congressman Beto O’Rourke, another presidential candidate in need of a boost, told Reuters.

“Warren’s rise has come from taking voters away from several different campaigns, and I think what you saw are candidates trying to get those voters back,” the adviser added.

TARGETING WARREN

Buttigieg went into the debate with a clear strategy of drawing contrasts between himself and Warren, according to a campaign adviser who asked for anonymity to discuss strategy.

The two candidates engaged in a fierce back-and-forth over healthcare policy.

The campaign believes that in attacking Warren, Buttigieg is also positioning himself as a viable alternative to Biden and stands to pick up supporters not only from his campaign but from other Democratic contenders.

Buttigieg may be best positioned to make a run at Biden. After a strong fundraising performance in the third quarter of the year, the mayor has more than $20 million in cash on hand and has already invested in more resources in the early voting states of Iowa and New Hampshire.

Biden, who has struggled with grassroots fundraising, has just $9 million in the bank.

A win in Iowa likely would give candidates like Buttigieg or Klobuchar a dramatic jump-start that could carry them forward into subsequent early contests, while a loss for Biden there could be a mortal blow to his effort.

Klobuchar, who has made winning Iowa central to her strategy, also arrived at the debate poised to distinguish herself from Warren, according to a source with her campaign.

She suggested that Warren’s progressive agenda would leave a lot of middle-class voters cold.

“I think simply because you have different ideas doesn’t mean you’re fighting for regular people,” Klobuchar told Warren.

The campaign source said the strategy worked: Klobuchar’s campaign raised more money in small donations after the debate than in any previous 24-hour stretch.

She still has a lot of ground to make up, however, with a national polling average of just under 2%.

After the debate, Warren spokeswoman Kristen Orthman said the senator from Massachusetts “took heat” as a result of her momentum, but “stayed focused on what’s broken and how she plans to fix it ... that’s how Elizabeth will win the nomination, beat Donald Trump and make big, structural change.”

Cory Booker, a U.S. senator from New Jersey, used the debate to position himself above the fray as the candidate who can unite the party’s warring moderate and progressive factions.

“While others were going after each other, Cory won the night by standing out as a leader, a unifier, and the adult in the room who refocused the conversation on the issues that matter most,” a Booker representative told Reuters.

Biden, who faced tough criticism in past debates from candidates such as U.S. Senator Kamala Harris and former U.S. Housing Secretary Julian Castro, had a relatively easy time of it on Tuesday from his rivals.

The prior attacks largely backfired on Harris and Castro. But Delacey Skinner, a Democratic strategist who has worked for Senate and gubernatorial candidates, said there was an even simpler reason why Buttigieg and Klobuchar did not go after Biden.

“I’d guess neither of them wants to alienate Biden supporters,” she said.