If anyone thought that Senator Elizabeth Warren would ease up on her battle with the White House over Treasury Undersecretary for Domestic Finance nominee Antonio Weiss, they can put such thoughts to bed. In a speech today at the “Managing the Economy” conference in Washington organized by several financial reform coalitions, Warren made clear that her fight is about much more than one nominee at the Treasury Department. She crafted a direct challenge to three decades of bipartisan collusion between government and Wall Street, in a highly unusual manner for any politician, let alone one recently drafted into the Senate Democratic leadership. The Weiss affair has become secondary to this bigger competition for what principles will shape the Democratic Party, and what role Warren will play in it.

At a conference ostensibly about the role of the Federal Reserve in economic policy, Warren pivoted to her main concern—Wall Street’s outsized influence on our government. She highlighted the 1,447 former government officials who lobbied for the financial services sector during the Dodd-Frank debate, and how big banks like Goldman Sachs and JPMorgan Chase meet with top regulators several times a week.

But she really wanted to talk about Antonio Weiss, and set his nomination in the context of who really runs financial policy when Democrats get into power. Last month, the White House nominated Weiss, a mergers and acquisitions specialist at the investment bank Lazard, for the number 3 position at the Treasury Department, and Warren immediately came out against the nomination. At the heart of the disagreement is the easy manner in which financial sector executives float in and out of government, a practice known familiarly as the revolving door.

As Warren pointed out, three of the last four Treasury Secretaries under Bill Clinton and Barack Obama worked for Citigroup at some point, and the fourth, Tim Geithner, was offered the Citi CEO job. Under the current administration, ex-bankers staffed jobs at the Federal Reserve, National Economic Council, Office of Management and Budget, U.S. trade representative, and dozens of other top policymaking positions. She even cited my report in The New Republic about Wall Street securities lawyer Sharon Bowen’s ascension to a commissioner slot on the Commodity Futures Trading Commission, which has worked out exactly how you would expect, with the agency rolling back and delaying scores of derivatives regulations pushed through in Dodd-Frank.

Warren has come under criticism from elites in the financial press for her opposition to Weiss, and she answers those critics directly. First of all, she corrected the assumption that her concerns stem entirely from Weiss’ participation in the corporate inversion between Tim Hortons and Burger King. Actually, Warren leads with the fact that Weiss’ experience advising “companies buying and selling each other” displays no real qualifications for this particular job. The New York Times even had to issue a correction when Treasury oversold Weiss’ expertise to one of their reporters.