For quite a while in this cycle, many questioned whether Bernie Sanders wanted to win the Democratic Party’s presidential nomination, or just go on tour. He steadfastly refused to attack Hillary Clinton on her credibility or integrity, and proclaimed at one point that he was “tired of hearing about” her e-mail scandal. Lately, the Washington Post’s John Wagner notices, that’s changed — and it coincides with Sanders’ win streak:

When Bernie San­ders launched his long-shot bid for the presidency 10 months ago, there were two words that rarely crossed his lips: Hillary Clinton.

Now he can’t seem to stop talking about her — and not much of what he has to say is very nice.

During a boisterous rally here, the senator from Vermont dinged Clinton for supporting a series of “disastrous” trade deals. He mocked her for refusing to release transcripts of paid speeches she gave to Wall Street firms. He said she was wrong to vote for the Iraq War in 2002.

Democratic observers tell Wagner that Sanders is risking his identity in going on the attack:

Analysts say Sanders’s decision to attack Clinton more aggressively is understandable: It’s what candidates who are behind tend to do. But in Sanders’s case, he risks damaging his brand as an anti-establishment politician who has boasted about never running negative television ads and pledged to stay positive in his bid for the Democratic nomination.

“When you’re promising to run a different kind of campaign, it’s never good to look like you’re running the same kind of campaign that other politicians do,” said Mo Elleithee, executive director of the Institute of Politics and Public Service at Georgetown University. “It’s a risk, but it’s a calculated risk, and one they seem willing to take.”

How exactly does attacking the establishment hurt one’s anti-establishment credibility? This is pretty basic politics and linguistics: to be anti something means to oppose it, and by opposing it one has to launch at least some criticism of it. The issue for Sanders is that he wanted to eat his cake and have it, too. He wanted to be anti-establishment without attacking the Clinton establishment, and that turned out to be impossible.

Ryan Lizza writes at the New Yorker that this has been the battle all along, whether Sanders wanted it to be or not:

Despite Sanders’s surprising victory last Tuesday in Michigan, where polls showed him trailing by an average of some twenty points, his odds of winning the nomination are slight. But his candidacy has exposed deep tensions within the Democratic Party. Long before Barack Obama attacked Hillary, during the 2008 campaign, for her “triangulating and poll-driven positions,” Sanders, who was elected to the House in 1990 and to the Senate in 2006, has been making the case against Clintonism. In the nineteen-nineties, he was a gadfly leftist in a party that was trying to seize the political center after twelve years of Reaganism. As Sanders noted in the debate in Flint, on March 6th, when Hillary was First Lady she publicly supported NAFTA, while he “was on a picket line” protesting it. Today, both candidates oppose the agreement—and many other aspects of Bill Clinton’s record.

Clinton’s 1992 campaign and his Administration reflected two political strains that still define the Party: one is populist, anti-Wall Street, and pro-regulation; the other is more austere, more oriented toward the New York financial world, and more laissez-faire. Clinton’s Labor Secretary, Robert B. Reich, pressed for more government spending, but the top economic adviser in the White House, Robert Rubin, a former Goldman Sachs executive and later the Treasury Secretary, ultimately persuaded Clinton to abandon many of the liberal spending priorities that he championed during his campaign and to focus instead on reducing the deficit. Later, Rubin also pushed to deregulate the financial industry. That polarity remains. Hillary Clinton is surrounded by Rubin’s acolytes; Reich, an old friend of Bill Clinton’s from their days together at Oxford as Rhodes Scholars, recently endorsed Sanders. …

Sanders “is tapping into something that is very deep and very profound inside the Democratic Party, which is this discontent with the system that is no longer producing for everyday people,” Simon Rosenberg, a Hillary supporter and the head of NDN (formerly the New Democrat Network), a liberal think tank in Washington, told me. “He has characterized Hillary as a champion of that system and as somebody who is actually a leader of the system, while he is the one that wants to change it.” Rosenberg added, “He’s not being perceived as a leftist. He is being perceived as somebody who is deeply in touch with a sense that something has gone wrong and that the system isn’t working.”

That’s also true of how Trump is perceived on the Right. The difference between the two, at least until now, is that Trump has explicitly run against the GOP establishment, especially the Bushes. Sanders is just catching up to his fight against Clintonism, or perhaps to put it more accurately, he’s being more honest about it now and putting aside the contrivance of the no-negative anti-establishmentarian.