With the Iowa caucuses fast-approaching, Bernie Sanders is enjoying a massive 58-point lead over Hillary Clinton among voters under 30. Perhaps more stunning is the fact that Sanders and Clinton were tied among these voters less than a month ago.

According to Reuters tracking poll, Sanders now leads Clinton 75-17 percent among Democrats under 30. At the beginning of 2016, the two candidates were tied among millennials, each receiving 47 percent support from young voters.

The wave has come as the Hillary Clinton campaign has stepped up its outreach to young voters and tapped former President Bill Clinton and daughter Chelsea Clinton for more public roles in the campaign.

At the end of last year, strategists close to the Clinton campaign speculated that young voters would give Clinton an edge, as they did not live through, or even know about, the political scandals that surrounded the Clintons in the 1990s.

“Mil­len­ni­als and Gen Xers are ac­tu­ally some of the most sup­port­ive of Hil­lary Clin­ton,” Demo­cratic poll­ster Celinda Lake told National Journal last year. “It’s the best of both worlds: While they don’t per­son­ally re­mem­ber the 90s, they have a sense that it was a much bet­ter time.” She added, “But they don’t re­mem­ber the scan­dals, they don’t care about Mon­ica Lew­in­sky.”

Lake’s comment obviously came before the Lewinsky and other scandals involving Bill Clinton resurfaced in the campaign.

In a speech at the end of December, GOP frontrunner Donald Trump said that Hillary “got schlonged” by Barack Obama in 2008. The expression was roundly criticized in the media as being a sexist insult. Hillary Clinton responded by accusing Trump of sexism.

Rather than apologize, however, Trump turned the tables and accused Hillary Clinton of having enabled Bill Clinton’s affairs and covered up allegations of Mr. Clinton’s sexual assaults against women.

In the weeks that followed, the media re-reported many of the past allegations against Mr. Clinton, and a number of accusations reappeared to retell their stories. The millennials may not personally remember the 1990s, as Ms. Lake notes, but they were quickly reminded of all the sordid details.

Many of the old allegations look very different in today’s light than they did 20 years ago.

In early December, Hillary Clinton led Bernie Sanders by seven points among Democrat voters under 30. The shift to Sanders has been one of the more dramatic moves ever witnessed in such a short period of time in a national presidential campaign.

While the Reuters tracking poll is a national poll, the overall trend could have an impact on the Iowa caucuses Monday. In 2008, almost a quarter of those voting in the caucuses were under 30. Barack Obama received 57 percent of their vote, far less than the support Sanders currently enjoys from these voters.

In 2008, in fact, voters under 30 equaled the number of seniors voting in the caucuses. Hillary Clinton won voters over 65, but only narrowly. Clinton won 45 percent of the vote of seniors, but against two major opponents.

If young voters again make up such a large share of the Democrat caucuses Monday, Hillary Clinton will need overwhelming support from older voters to squeak out a win in Iowa. Of course, many of those older voters she needs now were themselves part of the wave of young voters who lifted Barack Obama over her in 2008.

It seems unlikely that Hillary Clinton is more popular today than she was when those voters rejected her in 2008.