Donald J. Trump made clear this week that nothing was off limits when it came to attacking the Clintons, dusting off names like Monica Lewinsky and Paula Jones while calling former President Bill Clinton one of “the great abusers of the world.” Sexual indiscretions of the past, he said, are fair game in an election year.

But the numbers show that Mr. Trump, the billionaire developer and Republican presidential hopeful, might not be dealing with a hand as strong as he thinks when he reminds voters of Mr. Clinton’s history of infidelity.

Hillary Clinton’s popularity has had its peaks and valleys during her decades in the public spotlight, most recently rising to new heights when she was serving as secretary of state. Her other peak, according to polls, was in 1998 while her husband was embroiled in the Lewinsky scandal and facing impeachment.

Survey data from the Pew Research Center show’s Mrs. Clinton’s favorability rating jumping to 63 percent in August of 1998, four months before Mr. Clinton was impeached by the House of Representatives. In December of that year, as controversy about their marriage continued to swirl, her popularity climbed higher, reaching 66 percent.

“In contrast to her husband, Hillary Clinton continues to draw high marks from the public,” Pew found at the time. “Two-thirds of Americans say they admire Hillary Clinton’s decision to stand by her husband and nearly as many have a favorable opinion of the first lady.”

Figures from Gallup also showed Mrs. Clinton’s favorability rating rising as accounts of Mr. Clinton cheating dominated headlines. That rating, which was at 39 percent in 1992, remained high through 1999 before leveling off. It hovered from 40 percent to 50 percent in the 2000s and topped 60 percent again when she joined President Obama’s cabinet.

Shawn J. Parry-Giles, a communications professor at the University of Maryland, explained in her 2014 book about the role of gender in American politics that Mrs. Clinton was seen as more sympathetic and authentic as she endured the fallout from her husband’s affair.

“As she showed a clear sense of marital fortitude by staying with her cheating husband, her poll numbers would rise,” Ms. Parry-Giles wrote. “As the scorned and sad woman attracting sympathy from others, Clinton would more closely resemble the traditional ideals of authentic womanhood.”

Nearly 20 years later, Mr. Trump is betting that voters will view Mr. Clinton’s history as a liability as the couple seeks to return to the White House.

“She’s got a major problem that happens to be right in her own house,” Mr. Trump said at a rally on Wednesday. “We’ll go after the ex-president. It’ll come out well for us.”

Historically, however, that has not been the case.