Elizabeth Warren (remember her?) has so far withheld an endorsement in the Democratic presidential primary, though there’s little doubt where her loyalty lies. After all, it was the decision by the Massachusetts senator to forego a run that compelled her neighbor to the north, Vermont Sen. Bernie Sanders, to pick up her populist critique and carry it into the race against Hillary Clinton. Sanders has since built the message — of hostility toward what he frames as entrenched corporatism and the campaign finance system that sustains it — into a bona fide grassroots movement. Now on the eve of his first test against Clinton, in the Iowa caucuses on Monday, Warren is reemerging. What she’s offering in lieu of an endorsement is a more nuanced argument for Sanders than the one he’s made for himself.

Last week, on the sixth anniversary of the Supreme Court’s Citizens United decision, Warren took the Senate floor to decry it for allowing dark money to flood back into campaigns. She didn’t mention Sanders by name, but as she concluded, she channeled him: “A new presidential election is upon us,” she said. “Anyone who shrugs and claims that change is just too hard has crawled into bed with the billionaires who want to run this country like some private club.”

Then on Friday, Warren released an 11-page report arguing that the Obama administration’s approach to holding corporate lawbreakers criminally accountable has been “shockingly weak.” The report provides snapshots of 20 criminal and civil cases from 2015 in which she holds the feds went easy on wrongdoers — GM for its ignition switch problems; Novartis for an alleged kickback scheme with pharmacists; Massey Energy for its mine explosion; JPMorgan, Citigroup and others for manipulating exchange rates, and so on. In a New York Times op-ed promoting the report, Warren contends that aggressive prosecutions would not only signal to executives that they’ll be held to the same standard as everybody else, they could also spare working people who’d otherwise get gouged. In other words, Warren is arguing that by simply wielding the laws already on the books, rather than struggling to pass new ones, a president could strike a blow against the inequality now agitating the left. And all it would take is somebody in the White House committed to stocking the administration with likeminded enforcers.

Say what you will about its merits. But that’s a far more realistic case for how a Sanders presidency could differ from a Clinton presidency than the candidate has made. On the stump, Sanders pledges a massive expansion of government, to the tune of $18 trillion, and higher taxes to pay for it, while acknowledging it will require no less than a political revolution to push it through Congress. In all likelihood, Sanders’s bid will fall short and he’ll return to the Senate. Then, the measure of his campaign’s success will be how far it forced the party establishment to move to adopt his appeals, from the aspirational to the relatively practicable.