WASHINGTON -- Democratic presidential candidate Hillary Clinton on Sunday questioned Republican Donald Trump's business record and assailed his ideas. She also warned that if left unchallenged, Trump could "normalize himself" in the coming weeks as he seeks to broaden his political support.

Democratic rival Sen. Bernie Sanders of Vermont, meanwhile, pointed to polls that show Clinton with high percentages of unfavorable opinions and asked whether a choice between her and Trump in the fall would force voters to pick the "lesser of two evils."

As she contends with Sanders' unflagging critique from the left, Clinton said it is vital for her to pivot to confront Trump now, lest he successfully repackage himself for wider consumption rather than appealing to the Republican primary electorate alone.

"I do not want Americans and, you know, good-thinking Republicans, as well as Democrats and independents, to start to believe that this is a normal candidacy," Clinton said of Trump's campaign on NBC's Meet the Press.

"I know he has a plurality of Republicans who have voted for him," she said. "But I think in the course of this campaign, we are going to demonstrate he has no ideas. There's no evidence he has any ideas about making America great, as he advertises. He seems to be particularly focused on making himself appear great. And as we go through this campaign, we're going to be demonstrating the hollowness of his rhetoric."

Clinton also poked at Trump's failure to release his tax returns.

Told that Mark Cuban, a media executive and owner of the Dallas Mavericks, had expressed interest in being her running mate, Clinton said she was "absolutely" open to considering business leaders, not just elected officials.

"Businesspeople, especially successful businesspeople, who are really successful -- as opposed to pretend successful -- I think, have a lot to offer," said Clinton, whose campaign has begun taunting Trump with a #PoorDonald hashtag on Twitter, suggesting that he is not nearly as wealthy as he claims. Trump has cited an audit by the Internal Revenue Service as his reason for keeping his tax returns private.

"We've got to get below the hype," Clinton said. "I think we're beginning to find out, but I don't think we know enough, and that's why he should release his tax returns."

Friends, aides and supporters of Clinton describe her as a candidate who isn't rattled by what she expects will be Trump's increasingly direct attacks on her marriage and her husband's personal indiscretions.

In fact, Clinton believes that she can turn Trump's personal assaults to her benefit, they say, particularly among suburban women who could be crucial to her hopes in the fall, should she win the nomination. Her plan is never to engage in back-and-forth over the scandals. Instead, she'll cast Trump as a bully and talk about policy.

"I don't care what he says about me, but I do resent what he says about other people, other successful women, who have worked hard, who have done their part," she told an audience in Louisville, Ky., this month.

Trump has made clear that nothing is off limits. He described one of the allegations of past sexual misconduct involving Bill Clinton as a rape. "It's all fair," Trump said last week.

He drew a distinction between his personal history, which includes three marriages and public admissions of infidelity, with that of the former president.

"He was the president of the United States when certain things happened," he said. "My stuff is nothing when you take a look, in terms of a comparison."

Clinton said she wouldn't respond to those kinds of attacks.

"That's exactly what he's fishing for," she said on CNN.

Her supporters contend that Trump's slams on her character will motivate Democrats, particularly female voters, as long as Clinton stays focused on rising above those matters.

"I couldn't believe it, you blame the woman for male infidelity?" said Sen. Dianne Feinstein, D-Calif. "To me it was kind of bizarre that you would visit the sins of one on the other. I don't think there's any woman in America that doesn't understand that."

Trump has said his quarrel with Hillary Clinton's character is rooted in her involvement in past efforts to discredit the women linked to her husband, while portraying herself as a champion of women's issues.

Aides at her campaign headquarters in New York have closely studied the various strategies of the Republican primary contenders who tried -- and failed -- to deflect Trump's insults. They expect far worse to be directed at Clinton.

"It is no surprise he is running his campaign from the gutter, but Hillary Clinton doesn't care what he says about her," Clinton spokesman Brian Fallon said.

Information for this article was contributed by Julie Pace, Jeff Horowitz and Jill Colvin of The Associated Press; and by Amy Chozick of The New York Times.

A Section on 05/23/2016