BILOXI, Mississippi—Democrats, who are generally pretty happy with the idea of Hillary Clinton as their party's nominee in 2016, are pleased by a Washington Post poll that seems to knock down an attack on her. Karl Rove had first said that Clinton would face questions about the brain injury she sustained in December 2012 (the one that delayed her Benghazi testimony); then, in the friendly acres of Fox News, he said Clinton was an "old and tired" candidate. And yet:

Two-thirds of Americans in a new Washington Post-ABC News poll disapprove of the Republican strategist raising questions about Clinton's age and health in advance of her potential presidential run. The lopsided negative reaction to Rove's commentary—just 26 percent approve of his topic of criticism—includes majorities of every age group as well as Democrats and independents. 

Victory! Right? Well, no—it's not like Rove was trying to disqualify Clinton with one set of remarks. As Rove profilers quickly pointed out, he has done things like this before, and floated rumors just to get them into the zeitgeist. Once heard, they can't be unheard. It's one of the basic principles of language and memory. Say "don't think of an elephant," and the listener can't help but think of an elephant.

Rove, who despite his 2012 losses remains a sought-after pundit, is doing what other Republican strategists only wish they had the platforms to do. He is talking down Clinton in the hope that it emboldens the left to challenge her and emboldens a serious Republican to run for president. Talking with Republican strategists and campaigners, I hear less-measured versions of the Rove critique. That Clinton looks old. (No accident that the Drudge Report manages to find the worst AP photo of her.) That she's a weak and cold campaigner who lost a sure thing in 2008. "None of this is to claim that Clinton is an objectively strong candidate," wrote Jay Cost at the end of a piece that concluded Clinton had no serious primary foes. "She manifestly is not; otherwise she would be president right now." The magazine that published this column currently has a piece up mocking Clinton for being unable to sell out a speech at a discount. 

Democrats currently support Clinton in 2016 at a level no nonincumbent has seen this far ahead of a primary. All Republicans can really do about this is seed doubts that she can ever win. Not a good reason to cover every fart and thunderbolt from Rove, et al., just a way of understanding why he's doing it. He's not doing it to look good in a poll this week.