In her book released this year, Sen. Elizabeth Warren recounted a dinner she had with President Barack Obama’s chief economic adviser, Larry Summers, in April 2009, when Warren was the outspoken chairman of a congressionally appointed panel probing the government’s response to the financial crisis.

“Larry leaned back in his chair and offered me some advice. … He teed it up this way: I had a choice. I could be an insider or I could be an outsider. Outsiders can say whatever they want. But people on the inside don’t listen to them. Insiders, however, get lots of access and a chance to push their ideas. People – powerful people – listen to what they have to say. But insiders also understand one unbreakable rule. They don’t criticize other insiders.”

Warren ignored the warning.

And if the past few weeks are any indication, she can operate as an insider without giving her up outsider credentials. She’s remained outspoken, but has become even more influential. She hasn’t stopped throwing bombs at the rich and powerful, but she’s won a spot in Senate leadership, changed the shape of congressional debates over financial regulation and continued to draw widespread attention as a potential presidential candidate.

It all helps to explain why – for the 300 former Obama campaign officials who last week urged her to run in 2016 – she is the one they’ve been waiting for.

“Rising income inequality is the challenge of our times, and we want someone who will stand up for working families and take on the Wall Street banks and special interests that took down our economy,” they wrote.

Over the past week, Warren galvanized liberals across Capitol Hill against a government spending bill that weakened a key provision of the 2010 Dodd-Frank law tightening oversight of Wall Street.

The Senate may have passed the legislation late Saturday, but it was not before Warren and other liberals asserted their power in a confrontation with the White House, even winning over House Democratic Leader Nancy Pelosi, who had previously supported the legislation.

Warren is also in an unusually public battle with the White House and Treasury Department over Antonio Weiss, an investment banker tapped for a key Treasury position. White House officials say Weiss is sympathetic to Democratic views. But Warren has won over several colleagues in trying to block the nomination, saying the administration is too cozy with Wall Street.

It’s a topic she reprised in a speech Friday evening after losing the battle over the spending bill, in which see singled out Citigroup as an example of a bank with too much power.

“Enough is enough with Wall Street insiders getting key position after key position and the kind of cronyism we have seen in the executive branch,” she said. “Enough is enough with Citigroup passing 11th-hour deregulatory provisions that nobody takes ownership over but that everybody comes to regret. Enough is enough.”

Critics of Warren, even if they’re sympathetic to her view, would say that by taking absolutist positions, she won’t achieve much more than fiery rhetoric.

The history of Obama’s presidency is a story of compromises that disappointed liberals but achieved policy gains, including the Affordable Care Act.

To the degree Obama seeks congressional accords in his final two years, he will be forging them with Republican leadership. But should he move far in hopes of a compromise with the GOP, Obama will likely find Warren leading a liberal flank in opposition. It’s hard to know if she would succeed, but the past few weeks show that she has the influence to make a difference.