The effort must be all consuming. Now that Donald Trump is the last man standing in the Republican presidential race, Democrats are searching for the best way to convince voters he should never be allowed to set foot in the White House. Hillary Clinton and her allies seem to believe that using his own words against him will prove effective. The question is, Why would that work now when it hasn’t worked so far?

Television ads featuring a variety of statements Trump has made about women—which might reasonably be assumed to offend—started airing this week in the general-election battleground states of Ohio, Virginia, Florida, and Nevada. The ads are paid for by pro-Clinton super PAC Priorities USA. One shows women—young, old, black, and white—mouthing the words to comments from Trump. “Does Donald Trump Really Speak for You?” the 30-second ad asks ominously. Another starts with Trump proclaiming: “Nobody respects women more than Donald Trump.” It contrasts that with clips of him saying, “There has to be some form of punishment” for abortion and suggesting he would cut funding for Planned Parenthood. If it wasn’t already clear that the presidential election would focus on gender politics, it is now.

But will that do anything to hurt a politician who has so far seemed immune to harm? Trump supporters love the fact that, in their eyes, he tells it like it is, throwing political correctness out the window. Far from a liability, that has been a key reason for Trump’s success. Still, while the Republican candidate has convinced plenty of voters to side with him, there is reason to believe his controversial statements have taken a toll on his standing with women. A Gallup poll released in April indicated that Trump has become increasingly unpopular with women as the primary election drags on. In July 2015, 58 percent of women had an unfavorable image of Trump. By March 2016, that had jumped to a full 70 percent.

It seems likely that Trump being Trump has damaged his popularity—not necessarily with the conservative voters who have faithfully supported him, but with women who make up the broader electorate. “The Republican primary electorate is going to be more forgiving of him,” said Kelly Dittmar, a scholar at the Center for American Women and Politics at Rutgers University. “But when he tries to win over female swing voters, those moderates at the center, and unmarried women who will be key to this election, they may be more offended by things he has said than women who were already in his camp.” The teflon armor that has kept Trump safe so far may not protect him in the general election.

But if so many women dislike Trump already, why focus attention there? Jennifer Lawless, the director of the Women and Politics Institute at American University, suggests the ad campaign may not be so much about trying to make Trump even more unpopular with women as it is about making sure feelings of ill-will toward him don’t fade. “The Trump campaign’s efforts for the next few months will be to try and peel back some of that distaste,” Lawless said. “If Democrats are able to go out there and depict him as a candidate who will not, in fact, be good for women, that will keep them on stronger footing. It’s not necessarily about motivating women even further; it’s making sure that they stay turned off.”

Women are of course not a monolithic voting bloc. But attacks against Trump focused on women could prove effective across several categories of voters. They might motivate turnout for Clinton among Democratic women inclined to dislike Trump but who may not follow politics closely and might otherwise consider sitting out the November election. They could sway undecided voters to support Clinton over Trump, or persuade Republican women who will never vote for Clinton to also not vote for Trump. “Democrats have multiple paths to potentially win, and one that no one wants to talk about because it’s not good for democratic legitimacy is making sure that turnout is low on the other side,” Lawless said.

The ads could be effective for other reasons as well. Swing voters are likely to be more receptive to an attack against Trump that comes from a third-party group with an innocuous-sounding name (like Priorities USA) as opposed to from a candidate. “If you’re a strong partisan, you prefer to hear from your party or your nominee, but the closer you get to the middle of the partisan spectrum, the more likely you are to be swayed by outside group advertising,” said Erika Franklin Fowler, the co-director of the Wesleyan Media Project, which tracks and analyzes election advertising. “People tend to see candidates and parties as self-interested, whereas outside groups with generic names are less likely to generate backlash.” (For his part, Trump will do his best to tie Clinton to any advertising paid for by outside groups. Earlier in the week, he tweeted: “Amazing that Crooked Hillary can do a hit ad on me concerning women when her husband was the WORST abuser of woman in U.S. political history.”)

Still, the impact of political advertising shouldn’t be overstated. There are many moving parts to any winning campaign. Negatively defining an opponent can be an important part of an effective strategy, but it is just one part, and advertising is only one way to achieve that. “Campaign consultants and political commentators love nothing more than to dissect the messages of campaign advertisements,” wrote George Washington University’s John Sides in The New York Times in 2011, before ultimately concluding: “The power attributed to specific campaign ads is vastly exaggerated.”

As Democrats attempt to negatively define Trump in the minds of voters, they may struggle to concretely sum-up the supposed dangers of a Trump presidency, especially given how hard the candidate has been to pin down. Trump has defied conservative orthodoxy, and he continually seems to redefine his own positions. That will make it harder to come up with a comprehensive argument against him. The overall message of the ad blitz from Priorities USA has the potential to appeal to a broader electorate. It effectively suggests that Trump doesn’t have the temperament or the qualifications to be president. But Democrats risk watering that message down if it is filtered through the prism of how Trump talks about women or any other other single segment of the overall electorate.

Also, given the intense loathing on display for establishment politicians of all stripes this electoral season, voters may reject the argument that Trump isn’t presidential. Sure, he’s not the typical politician, but that’s precisely why his supporters love him. Making people feel uneasy about the prospects of a Trump presidency may not be enough to convince them to vote against him. Even if voters don’t like what they see of Trump in ads, they are sure to weigh that consideration against many other factors, including whether they think that Trump—with his straight talk and promises to “Make America Great Again”—will be better for the country than the alternative.

As Democrats look for the best way to build a case against Trump, they will also have to contend with the fact that the Republican candidate has proved remarkably adept at negatively branding his rivals. Frequently, he does so before they have successfully managed to land an attack against him. Trump already seems to have settled on a concise attack against Clinton, calling her “Crooked Hillary” on Twitter. That’s sure to stick in the minds of voters, and it plays on a long-standing vulnerability for Clinton: The perception that she may not be trustworthy. As the advertising blitz builds up and the next chapter of the presidential election opens, it will soon become apparent whether Trump can continue to defy the unofficial laws of politics.