Senator Elizabeth Warren made headlines this week when she called Republican presidential frontrunner Donald Trump a "loser" in a series of passionate tweets. It's one of the few times she's waded into the maelstrom of this year's presidential election, and when it comes to the contentious race within her own party for the nomination—between former Secretary of State Hillary Clinton and Vermont Senator Bernie Sanders—she's preferred, so far, to keep her cards close to the vest.

Warren joined Jim Braude and Margery Eagan on Boston Public Radio to weigh in on Trump's response and the reason she hasn't endorsed either Clinton or Sanders just yet. 

MARGERY EAGAN: Senator Warren, we could really get a ratings boost here—and it's pledge time and everything else—if you reveal on this show who you're going to endorse. Because really, what more is there to know—you know Hillary Clinton and you know Bernie Sanders. How about it?

SEN. ELIZABETH WARREN: The thing is, this primary has been such a good thing for the Democratic Party and, frankly, for the whole country. I don’t want to try to shut that down yet. I think it’s been good to have Democrats out there. We talk about issues. We talk about how a kid is going to get an education without getting crushed by student loan debt, how we’re going to better rein in Wall Street than we have in the past. Having those debates does two things: it helps us clarify what it means to be a Democrat and what kind of things we think are the key Democratic issues right now, and man, does it separate us from what’s going on on the other side...I think that right now it’s better to keep it open, keep the door open, and let the candidates get out there and make their cases directly to the people. I think it’s good.

JIM BRAUDE: Senator, you've branded Donald Trump a racist, a xenophobe and a misogynist, but isn't he tapping into something with the public that, frankly, most Democrats other than maybe you and a few others have been talking about forever: economic insecurity, anger?

WARREN: Yes. You know, a lot of people are tired that Washington works great for the biggest corporations, for the wealthiest individuals, for anybody who can hire an army of lobbyists and lawyers to rig the system in their favor. I get the frustration people feel. I feel it. But the answer is not the one that Donald Trump offers. The answer is to demand our government work for us, to fight back against the corporate takeover of government, not to blame our problems on Muslims or call women fat pigs. That’s not going to fix anything.

BRAUDE: But isn't the first half of what I'm saying true? With the exception of Bernie Sanders, I think a lot of voters feel the other Democratic candidate, Secretary of State Clinton, is late to the fair. They've been very tentative on this issue and now all of a sudden they're jumping on the Warren-Sanders bandwagon. But Democrats are as much at fault about the state we're in as Republicans, aren't they?

WARREN: Well, that’s what I said. I think the problem is that Washington has worked for those at the top for decades now. This didn’t all just happen in the last hour and a half. This has been going on since the late 70s, early 1980s, where the lobbyist class has taken over that place. You just watch it year after year after year, decision after decision after decision. You’ve got the same set of people just tilting the game a little bit in their favor on every single rule, on every single hearing, on every single outcome. After a while we end up where we are now. And that is: with a Washington that works, with an economy that works, great for the top 10%—and just isn’t working at all for the rest of America.

EAGAN: One of the problems Hillary Clinton has had—the trust issue—is linked to people suspecting she has too close ties to Wall Street. You were asked by Norah O'Donnell on MSNBC whether she should release these Goldman Sachs speeches, and you didn't really answer the question. Wouldn’t it be better, if she is the nominee, to have them now released instead of something damning in October, assuming she wins?

WARREN: Look, there’s been way too much coziness with large financial institutions on both sides of the aisle. It's something I worry about, it’s something I’ve fought against for years. But you’re asking about what advice I’d have for Hillary. Look: I have the same advice for her publicly and privately, and my advice focuses on the future: on what she’s going to do to hold Wall Street accountable and whether she’s going to surround herself with advisers who have real independence from the financial industry in the future. That’s what matters to me, that’s the advice I’ve given privately, that’s the advice I’ve given publicly. I’ll be blunt: that’s the advice I’m going to keep right on giving.

BRAUDE: Why should a voter in this election not assume the worst: that she’s not going to hold big money and Wall Street accountable?...Why not say to her: come clean and let the world know you were as tough as you say you were so there aren’t suspicions?

If Donald Trump thinks using Scott Brown's old hate-filled attacks on my family is going to shut me up, then he should think again.

WARREN: Like I said, it’s up to her to decide how she’s going to run her campaign. What I’m making clear is my part of the advice, and my part of the advice is: find a way to make clear to the American people that you’re going to hold Wall Street accountable, and you’re not going to surround yourself with a bunch of people who are accountable to the financial services industry or other big corporations. That’s the heart of it, and that’s where I’m going to stick and that’s where I’m going to keep asking every single day.

BRAUDE: If she had asked you a year or so ago, 'Should I give a speech to Wall Street for $250,000?' What would you have said to her?

WARREN: Look, I don’t give speeches like that. On the other hand, what can I say? I don’t get invited to give speeches like that, so there’s probably a reason I don’t get invited. But no. I wouldn’t.

EAGAN: You’re a great campaigner, and this race…has turned into almost your campaign speech. Lots of people think you should’ve run for president. Donald Trump, when you went after him, went after you, saying you have as much Indian blood as he has, attacking you on the Native American stuff. Is part of the reason you didn’t run is that you wouldn’t have to put up with this kind of thing from the GOP?

WARREN: No. Donald Trump is a bully and that’s what bullies do. Scott Brown tried the same thing, and if Donald Trump thinks using Scott Brown’s old hate-filled attacks on my family is going to shut me up, then he should think again. It didn’t work before, it’s not going to work this time. I’m doing what I promised the people of Massachusetts I would do. I’m out there in Washington every single day busting my tail to try to level the playing field, to try to loosen the stranglehold that Wall Street has on our government.

BRAUDE: If anyone didn’t know you were smart, the fact that you asked to speak first at the St. Patrick’s Day breakfast so you could leave shows wisdom beyond your age...

WARREN: Let me just say, I’m dealing with a cold and I would’ve loved to have watched every bit of the St. Patrick’s Day, ahem, ahem.