Hillary Clinton watches President Clinton pause as he thanks those Democratic members of the House who voted against impeachment in 1998. (Susan Walsh/AP)

It seems to be taken as something of an article of faith among supporters of Donald Trump and by Trump himself that the reintroduction of the Monica Lewinsky scandal would be detrimental to Hillary Clinton's candidacy. It's been nearly 20 years since the story of Bill Clinton's indiscretions first emerged, and it's not immediately clear what the effect of focusing on the subject might be. But when the story broke, the effect on Hillary Clinton was a quick spike in her favorability rating, particularly among men.

Matt Drudge had the first story about the Lewinsky affair in mid-January 1998. The Washington Post had polled on Hillary Clinton's favorability the previous March and then several times in the wake of the revelation. Among all Americans, Clinton went from 42 percent viewing her positively to 52 immediately after and 60 percent by the end of January. By the end of the year, her favorability was at 64 percent.


(The Washington Post)

The pattern of approval for Clinton over time was that women viewed her more positively than men, and that Democrats viewed her more positively than independents, who viewed her more positively than Republicans. After the Lewinsky story came out, Clinton's approval ratings jumped across the board. By November 1998, her approval had gone up about 10 to 15 points with Democrats, independent women and Republican women. Among Republican and independent men, it increased by at least 25 points. Men generally were about as likely to view Clinton positively as women had been.


(The Washington Post)

More broadly, Clinton was seen as sympathetic. In February 1998, CNN and Gallup asked Americans whether they admired Clinton for how she'd handled the Lewinsky affair; 72 percent said they did. In August, Fox News asked whether people thought Clinton was a strong woman for sticking with Bill Clinton or if she was being foolish. Nearly 6-in-10 said she was a strong woman. (That same month, Trump appeared on Fox News to defend Bill Clinton, arguing that Clinton was being hounded by "truly an unattractive cast of characters.")

Hillary Clinton's favorability sank in 1999, perhaps because her office announced that she was planning on exploring a run for Senate the following year. A pattern we've seen over time is that Clinton's favorability is tied to her involvement in electoral politics. As secretary of state and as first lady, she was isolated from the sort of criticism she faced as a candidate for Senate and the presidency.

That's one reason that it's hard to extrapolate from what we saw with Clinton's favorability in 1998 to the present. It's fraught for Trump to attack Bill Clinton's infidelities, given his own. Arguments that Clinton defended her husband against his accusers two decades ago are a little more complicated.

Update: My colleague Greg Sargent notes that consultant Rick Wilson spoke in May about testing the affair as a line of attack in the 2000 race. "The blowback from trying to use Bill against Hillary was through the roof," Wilson said. "Women thought she deserved that Senate seat because of what Bill had done."

Last weekend Trump made an explicit reference to the controversy, declaring on Twitter that he might invite Gennifer Flowers, with whom Clinton had an affair, to the first debate. The response to that suggestion — condemnation followed by the campaign's announcement that no invitation was ensuing — suggests that the toe dipped into this particular pool found the temperature a bit uncomfortable.

Trump desperately needs to bring white college-educated women back to his campaign. They supported Mitt Romney in 2012 but have rejected Trump this year. It seems unlikely that the strategy of digging up the Clinton affairs will resonate with that group. (Consider that by November 1998, nearly half of Republican women viewed Clinton favorably, an unthinkable occurrence now.)

What's driving this is probably at least in part a sense from Trump that he can throw Clinton off her game, or, potentially, cause her personal discomfort. Trump's team is replete with longtime anti-Clinton agitators, including Roger Stone, Steve Bannon and David Bossie. It may simply be an untested belief among this group that the 1990s scandal will be politically crippling.

If the reaction is anything like what she saw 20 years ago, though, Clinton might just welcome it.