BOSTON (CBS) – Former public school teacher turned big-time law professor Elizabeth Warren is an academic at heart. So when the Massachusetts senator/Democratic presidential candidate sat down with me Friday morning for an exclusive interview, it wasn’t surprising that she responded to a question about President Trump’s decision to kill Iran’s chief military commander with a bit of a history lesson.

“We never should have been in this position to begin with,” she said. “This assassination of Gen. Soleimani is reckless and it has been part of an escalating series of attacks that the Trump administration has put forward. And it has put our troops at risk, it has put our diplomats at risk and they’re already changing their story about the whole thing.”

“Keep in mind where this started,” Warren said, “We had a deal with Iran and our allies that Iran would not develop a nuclear weapon. Iran was abiding by the deal when Donald Trump all on his own said we’re gonna get out of that deal, very provocative.”

Warren’s campaign has proven provocative in its own right, with her insistence that “bold, structural change” is needed in a wide range of government policies.

When we cited statistics showing the relatively robust economic health of the New Hampshire middle class, Warren said she saw things quite differently, citing burdensome student loan debt as a drag on economic mobility and opportunity. And she rejected the notion that the middle class is prospering: “I just don’t see it that way, and that’s sure not what I hear from people when I’m there.”

But a telling moment in the interview came when we asked if she will vote for the U.S.-Mexico-Canada Agreement, the NAFTA update that won broad bipartisan support in the House late last year and has the endorsement of major labor unions.

“Workers have had the legs taken out from underneath them and this agreement makes improvements,” she said. “It’s gonna help open up some markets for farmers, they need that stability. It’s gonna help with enforceable labor standards and that’s gonna be useful. We really need trade negotiations going forward that make sure anyone who wants access to our markets is actually helping us in the fight against climate change and helping build an economy that works for everybody in the US.”

By contrast, Sen. Bernie Sanders, perhaps her most important competitor in New Hampshire, where the economy is closely tied to international trade, adamantly opposes the new deal, saying in a statement that “a re-negotiated NAFTA must stop the outsourcing of U.S. jobs, end the destructive race to the bottom, protect the environment, and lower the outrageously high price of prescription drugs. Clearly, Trump’s NAFTA 2.0 does not meet these standards.”

“How does that illustrate the difference between you and him?” Warren was asked Friday.

“I want to see improvement for our farmers and workers. It’s not as much improvement as I’d like to see but right now they’re in a terrible hole where Donald Trump has put them. I want to get them out of that hole.”

“And the contrast with Sanders is?”

“Well, Bernie sees this differently, obviously…. you’ll have to ask Bernie his reasons.”

That non-response was typical of Warren’s campaign-long reluctance to engage with Sanders (and he with her). But it also seemed like a missed opportunity to draw a respectful contrast on an issue of great economic importance to voters, a comparison that might have helped deflect the criticism that Warren is too confrontational to govern properly from her onto him.

And with less than forty days to go until New Hampshire voters must decide between the two leaders of the party’s left wing, time is running out.

You can watch Jon Keller’s entire interview Sunday at 8:30 a.m. on WBZ-TV