Hillary Clinton is seen aboard the campaign bus in Cleveland on the third day of a bus tour through Pennsylvania and Ohio.

July 31, 2016 Hillary Clinton is seen aboard the campaign bus in Cleveland on the third day of a bus tour through Pennsylvania and Ohio. Melina Mara/The Washington Post

The former secretary of state, senator and first lady is the Democratic nominee for president.

Former secretary of state Hillary Clinton campaigns in key states in her quest to become the Democratic nominee for president.

Former secretary of state Hillary Clinton campaigns in key states in her quest to become the Democratic nominee for president.

When Hillary Clinton reached the stage of the Col Ballroom, 58-year-old Mark Hammes shouted himself hoarse. “Give ’em hell!” he roared in a rasp that turned heads.

After the speech, he rifled through his wallet for the document he uses to defend Clinton against her multiplying critics — a list, clipped from a newspaper, of the many attacks on American embassies. All of them were worse than the 2012 Benghazi attack, so why did people keep attacking Clinton?

“Here’s Lebanon — 275 Marines killed,” said Hammes, pointing to a disaster that happened under President Ronald Reagan. “Somebody had the audacity to tell me, ‘Well, none of them were diplomats.’ Come on! One diplomat is worse than 275 soldiers? You can be stupid, but not that stupid.”

Another Clinton backer, Margie Schwaniger, 64, sounded exasperated at what she thinks is an unfair obsession with the email scandal that has haunted the Democratic presidential front-runner for months and has now escalated.

“It’s the media,” she said. “Even today — ooh, the emails! . . . There’s no new information on that story, but if you listen to NBC, they’re all after the drama.”

View Graphic Catch up on the controversy and read the emails

As the Iowa caucuses near, Clinton’s supporters here are feeling defensive. What once seemed to be a coronation in the making has turned into a real battle, exposing weaknesses that could hamper her through future primaries and, if she wins the nomination, a hotly contested general election.

The challenge from Sen. Bernie Sanders, once welcomed as a way to tune up the presumptive nominee, has highlighted her ties to unpopular Wall Street banks and accentuated her image as an establishment politician in a year of anti-establishment fervor. Her handling of the email controversy, which reemerged Friday when the State Department said that 22 emails that passed through Clinton’s private server when she was secretary of state contained “top secret” information, has laid out a road map for Republicans to tear away at her commander-in-chief credentials. A lingering FBI inquiry into whether the server put national secrets at risk adds to a sense of uncertainty.

Many Democrats who plan to caucus for Sanders worry that the perception by some of Clinton as dishonest has made her less electable than the democratic socialist from Vermont who honeymooned in the Soviet Union. On Friday night, at a Sanders stop just blocks away from Clinton’s, the complaints tumbled forth.

“As a woman, I’d love to have a woman in the White House, but she’s not the one,” said Spring Briggs, 36. “Her trust has been ruined, time and again. All these lies. And it’s not gotten better.”

“She seems too pre-scripted,” said Jerry Miller, 40, a worker at the nearby John Deere plant. “Her and Bill made their way to the White House, and don’t get me wrong, things were running really well. But they forgot how everyday Americans deal with certain things.”

Miller’s 18-year old stepdaughter, Alyssa McCorkle, did not remember the Bill Clinton era. Yet she has absorbed negative stories about Hillary Clinton. “When I hear about Benghazi and I hear about the secret emails. I don’t want a candidate for president to maybe be indicted,” she said.

The email scandal was fresh again, but Miller’s phrase — “everyday Americans” — harked back to Clinton’s April 15 launch video. She had followed it with a road trip to Davenport, which set the tone for the coming bruising. A campaign aide made sure to invite some locals to a coffee shop, which drew mockery. “Campaign staff DROVE ‘ordinary’ Iowans to Hillary’s first campaign stop,” screamed a headline in the Daily Mail, a British tabloid.

The Fix's Chris Cillizza previews the Iowa caucuses, looking at what the outcome could mean for both Democrats and Republicans. (Peter Stevenson/The Washington Post)

At the time, Clinton enjoyed a net favorable rating of six percentage points in the Gallup poll — down from her highs at State but better than any Republican seeking the presidency. Among Democrats, her net favorable rating was in the high 50s. Both numbers waned all year, bouncing back after Vice President Biden belatedly decided against a primary challenge, then — more surprising to Democrats — waning again.

The email story has wounded Clinton without any effort from Sanders. He helped Clinton deflect the issue during an October debate when he said that Americans were “sick and tired of hearing about your damn emails.” In a statement Friday evening, Sanders called the investigation “a legal process in place which should proceed and not be politicized” and urged Iowa to continue its “serious discussion of the issues.”

Sanders was able to say that because the issues have cut his way, and Republicans see a general election where they could exploit that. To their surprise, the Sanders who is seen only though the prism of a Clinton challenge and a populist agenda — the Sanders not easily shoved aside as a socialist — has become broadly popular.

“If somebody had told us a year ago that Sanders would be the most liked candidate in the presidential race, we would have told them they were crazy,” said Stuart Stevens, a strategist for Mitt Romney’s 2012 GOP campaign.

When Sanders entered the race, many Clinton supporters welcomed him as a grandfatherly figure who could nudge the front-runner to the left but who lacked the cross-demographic appeal to defeat her.

Instead, to many liberals, Sanders had made Clinton’s policy shifts look timid and insincere.

She praised early versions of the Trans-Pacific Partnership, only to turn against it amid criticism from the left. She liked the idea of states and localities setting minimum wages, then came out for a national increase to $12. She held off until September before opposing the Keystone XL Pipeline, a position that lined up with Sanders’s.

In Davenport, although Sanders did not mention Clinton’s name, activist and intellectual Cornel West called her out repeatedly in his introduction.

“We know the difference between a small ‘D’ Democrat and a Wall Street Democrat, capital D,” said West, with a vigor that bordered on ecstasy.

Republicans have begun to exploit the liberal disquiet surrounding Clinton. In Iowa, the Ending Spending Action Fund, largely bankrolled by Chicago Cubs co-owner Todd Ricketts has put $600,000 into an ad cheekily describing Sanders as “too liberal.”

Dan Backer, treasurer of the conservative Stop Hillary super PAC, said that Republicans could take advantage of how many in the Democratic left feel uneasy.

“When you say she’s in Wall Street’s pocket, that’s the sort of thing that will hurt enthusiasm” among liberals, Backer said. “Progressives don’t see the difference between her and any Republican.”

In Davenport, and in all of her closing rallies, Clinton has tried to change that by portraying herself as a reliable progressive with feet more firmly planted than Sanders. He spoke in broad terms, with national statistics on poverty. Clinton told granular, ripped-from-the-evening news stories of local companies letting Iowa down with tax inversions — “absolutely un-American.”

“I’d rather under-promise and over-deliver,” she said, one of several elliptical references to an opponent who assured his 3 million donors that they had joined a “political revolution.”

Die-hard Clinton supporters say that they appreciate her will to survive.

“I just think Hillary has stood for the values that I am for for a long time,” said Mary Stevens, of Marshalltown.

Asked whether any of the negative headlines that have emerged during the campaign give her pause, Stevens shook her head.

“She has withstood a lot, and she has admitted when she’s made some mistakes, just like everybody,” Stevens said.

As Clinton’s supporters left the venue, they got a hard, well-lit look at a banner someone had draped across an abandoned building.

“Hillary lied. Four people died.”

Anne Gearan and John Wagner in Iowa contributed to this report.