This morning, Senator Elizabeth Warren gave the keynote address at Netroots Nation, the highest-profile gathering of liberals on the political calendar. It wasn’t the greatest speech ever given, but it highlighted why so many liberals wish Warren would run for president, and the limits of liberal enthusiasm for Hillary Clinton. As actor Mark Ruffalo said after bounding on to the stage as Warren departed, “Wow, Elizabeth Warren, right? Wow.”

Warren is clearly tapping into something significant happening among Democrats. As Noah Weiland puts it, her recent reception has been “indicative of the forces propelling her to an even more prominent stature in liberal circles,” and her message is going “a long way with activists yearning for strongly-principled progressives in Congress,” who are displaying an “increasing urgency to make something more of her popularity.”

Much of this was on display today. Warren began her speech with an old story about how she was told that trying to create the Consumer Financial Protection Bureau was a fool’s errand, because it would anger the big banks and they have too much power. It was perfect for an audience of liberal activists, not just because of how they feel about the banks, but because it tells a story of liberals (or this one liberal) having the guts to take on powerful, wealthy interests and winning, by using government as a tool to restrain those interests and work on behalf of ordinary people.

The theme of Warren’s speech, repeated multiple times, was this: “The game is rigged and it isn’t right.” It’s an excellent theme for a presidential candidacy, because it explains what’s wrong with the country, how it could be changed (un-rig the game), and why this particular person is the one who can bring us to that better future.

At the moment, however, Hillary Clinton doesn’t yet have a simple, compelling story that encapsulates her candidacy (though she has plenty of time to come up with one). She couldn’t tell the same story Warren tells, because she is a fundamentally establishment figure. Her whole career has been about mastering existing institutions and power relationships. Rightly or wrongly, she can’t tell an activist story; she’s an insider who has sought to achieve her goals from the inside.

As such, when Clinton does embrace populism, it’s an insider’s populism, presented without the kind of rabble-rousing and even anger that someone like Warren can offer. It would be odd to hear Clinton say, as Warren did, “We can whine about it. We can whimper about it. Or we can fight back.” Clinton doesn’t talk in those kind of pugilistic terms.

Nor does she talk in the explicitly ideological terms Warren does, about the power and rightness of “progressive values.” Clinton will certainly attack Republicans, but not conservatives — she can be an intense partisan, but not nearly so intense an ideologue.

Of course, what works when speaking to an audience of activists isn’t necessarily what works when talking to the whole electorate. The fact that Hillary Clinton is a much more practiced and careful politician than Elizabeth Warren may well be more strength than weakness. And if Clinton is the nominee in 2016, the Democratic base will be united behind her. But it will likely be more a calm, reasoned decision than a blissful infatuation.