<a href="https://www.nytimes.com/2019/11/01/us/politics/iowa-democrats.html" target="_blank" rel="noopener noreferrer">Warren Laces Into Rivals as Iowa Campaign Grows Combative</a>  <font color="#6f6f6f">The New York Times</font>

Ms. Warren said “complacency does not win elections,” as she pushed for big changes, while moderates like Pete Buttigieg and Joe Biden vowed they could unite the country.

“Hope and courage wins elections,” Elizabeth Warren said at a Democratic Party dinner on Friday night in Des Moines. “I’m not running some consultant-driven campaign with some vague ideas that are designed not to offend anyone.’’Credit…Jordan Gale for The New York Times

DES MOINES — Displaying a new assertiveness toward her Democratic opponents, Elizabeth Warren laced into her chief political rivals, warning on Friday night that the country was in a “time of crisis” and arguing that Democrats would lose in 2020 if they nominated “anyone who comes on this stage and tells you they can make change without a fight.”

Speaking to thunderous applause during the party’s biggest Iowa political event of the year, Ms. Warren denounced candidates in the presidential race who opposed bold ideas in favor of more moderate solutions, in veiled attacks on Joseph R. Biden Jr. and Pete Buttigieg.

“Fear and complacency does not win elections,” she said at the Iowa Democratic Party’s fund-raising dinner. “Hope and courage wins elections. I’m not running some consultant-driven campaign with some vague ideas that are designed not to offend anyone.”

Befitting her front-runner status, Ms. Warren was the target of heated attacks from three of the first five speakers on the stage: Mr. Biden, Mr. Buttigieg and Kamala Harris. None of the candidates mentioned one another by name, though Mr. Biden and Mr. Buttigieg both presented themselves as more capable of uniting the country.

“We will fight when we must fight but I will never allow us to get so wrapped up in the fighting that we start to think that fighting is the point,” Mr. Buttigieg said.

Mr. Biden, who spoke directly after Mr. Buttigieg, extended the theme, saying, “If you can’t bring the country together we’re in real, real, real trouble.”

Even Ms. Harris, whose campaign is lagging to the point that she may not qualify for the party’s December debate, attacked Ms. Warren personally for the first time.

“I’ve only had one client in my life — the people,” Ms. Harris said of her career as a prosecutor. “Unlike others, I’ve never represented a corporation.”

The sharp exchanges underscored the urgency motivating the candidates as the race enters its final phase ahead of the Iowa caucuses three months from now.

The dinner occurred on one of the most consequential days of the race so far, with Ms. Warren, under pressure from other candidates over how she would pay for “Medicare for all,” finally introducing a long-awaited, $20.5 trillion proposal that immediately drew a fierce attack from her chief rival, Mr. Biden.

Mr. Biden declared that under his health care plan, there would be “no increase in taxes for the middle class. None, none, none,” a shot at Ms. Warren’s delay in articulating whether such taxpayers would see tax increases. Instead, Mr. Biden promised an opportunity to “buy into a Medicare-like proposal.”

The Biden, Buttigieg and Warren campaigns each bought large sections of the 16,000-seat Wells Fargo Arena here for supporters to cheer on their candidates. Mr. Buttigieg’s section was particularly enthusiastic, clapping thundersticks and waving flashing lights throughout his address. Ms. Warren’s fans were also spirited, unfurling a banner during her speech with the words, “Win with Warren.”

Bernie Sanders, while speaking at the event, brought no supporters, electing to lead them in a march outside instead, part of a pattern of the independent senator’s antipathy toward Democratic Party functions.

At the same time, the candidates have been wooing voters with bus tours, rallies and town hall-style events. Ms. Harris, the California senator who is trying to revive her campaign, has taken to cooking Sunday night dinners in supporters’ homes and plans to spend Thanksgiving in the state.

The surge in attention on Iowa coincides with a more contentious phase of the race, marked by aggressive campaigning and an increased willingness to go on the offensive.

Mr. Sanders, the senator from Vermont, and Mr. Biden, the former vice president, have resumed their attacks on each other, with back-and-forth sniping in the last week about Medicare for all and super PACs. Mr. Buttigieg and Amy Klobuchar have shown an increased willingness to go after Ms. Warren, the senator from Massachusetts.

Hours before the dinner was to begin, Former Representative Beto O’Rourke of Texas announced the end of his presidential campaign. His departure was so sudden that supporters had already planted scores of his signature black-and-white campaign signs outside the arena.

Lower-tier candidates looking to energize their campaigns have also been more pugnacious: Representative Tulsi Gabbard of Hawaii, for instance, has amped up her criticisms of the Democratic National Committee, the news media and even Hillary Clinton, who is not in the race.

But nowhere has the battle been more intense than at the event on Friday, with candidates trading barbs less on specific policies, and more on political ideology.

“We need big ideas, and here’s the critical part: We need to be willing to fight for them,” Ms. Warren said. “It’s easy to give up on a big idea, but when we give up on big ideas, we give up on the people whose lives would be touched by those ideas.”

Of the top-tier candidates, only Mr. Sanders — the sole candidate to stand stationary and speak from note on a lectern — did not attack his opponents, instead delivering a version of his standard stump speech that championed the working class and took aim at corporate interests and the rich. He quoted Franklin D. Roosevelt and Nelson Mandela and provided please for his signature policy proposals, including “Medicare for all” and tuition-free public college.

He also announced his campaign was donating $20,000 to the Iowa Democratic Party in a symbolic show of solidarity even as he continues to eschew traditional party politicking.

The crowded and diverse field — there are still 17 candidates — has proved challenging for contenders outside the top tier. While nine have qualified for the party’s November debate in Atlanta, just four are guaranteed a spot for the December debate in Los Angeles.

A poll taken this week of likely caucusgoers by The New York Times and Siena College shows the top four candidates locked in an extraordinarily tight race. Ms. Warren held a narrow advantage, with the support of 22 percent of voters, while Mr. Sanders drew 19 percent and Mr. Buttigieg 18 percent. Mr. Biden, who entered the race as a front-runner, had the backing of 17 percent of likely caucusgoers, much weaker than his position in national polls.

For Democrats who had been inclined to support Mr. Biden but now find themselves shopping around, that means the moderate choices are limited to Mr. Buttigieg, the mayor of South Bend, Ind., and Ms. Klobuchar, the senator from Minnesota, with other would-be options like Senator Cory Booker of New Jersey falling out of the conversation.

Susan Swift, a 58-year-old yoga teacher from Dubuque, said at a Biden event Wednesday that even after watching nine months of campaigning she was still trying to decipher the field.

Ms. Swift said she liked the former vice president for “his experience,” but had become more impressed with Mr. Buttigieg the more she had seen him.

“Did you see the pluck that that guy had in the last debate?” she said. “Seriously? I was like, ‘You just won my heart.’”

Conversations this week with 24 of Iowa’s 99 Democratic county leaders revealed moderate Democrats moving from Mr. Biden toward Mr. Buttigieg and Ms. Klobuchar, who the county officials said had benefited from strong debate performances and repeated trips to the state.

Mr. Sanders, who fought Mrs. Clinton to a draw in Iowa four years ago, has struggled to retain support in the party’s most liberal pockets. Some of his anti-establishment backers have gravitated to candidates even more outside the mainstream, like the entrepreneur Andrew Yang and Ms. Gabbard.

Zach Simonson, the Democratic chairman in Wapello County, backed Mr. Sanders in 2016 and said he was now torn between Mr. Sanders and Ms. Warren.

“I was all in for Bernie in 2016, but with Warren in the race, some of the weaker parts of his candidacy are magnified,” Mr. Simonson said. “He’s got a very reasonable critique of the national Democratic Party institution, but from campaigning so much on the outside, I don’t know if he’ll be ready to take the role of national standard-bearer for all Democrats after the convention.”