Cooper Allen, and Paul Singer

USA TODAY

It was their first head-to-head debate and their last before Tuesday's primary.

Here are top takeaways from Hillary Clinton and Bernie Sanders' MSNBC debate Thursday night in New Hampshire:

The progressive question

At their most basic level, presidential campaign strategy can be distilled like this: appeal to your party's base during the primaries, then move to the center for the general election. So it has been in recent days between Sanders and Clinton as their campaigns sparred over whether she was sufficiently progressive to carry the banner of the Democratic Party. He's cited her ties to Wall Street and a well-funded super PAC as evidence of her shortcomings as a true liberal champion. Clinton took on the critique aggressively Thursday night, saying she wasn't sure who could live up to his lofty standard.

"Under his definition, President Obama is not progressive because he took donations from Wall Street," she said.

The exchange allowed Clinton to make what is a central argument of her campaign: that she's ideologically aligned, for the most part, with the party's base, but that she's "a progressive who gets things done." She also further positioned herself as someone who would be a defender of the Obama legacy, particularly the Affordable Care Act, which she called "a major achievement of President Obama." Sanders, she says, would start over on health care, which he said was "inaccurate." Clinton seemed perfectly comfortable positioning herself as the pragmatic progressive to Sanders' political revolutionary, but when the debate homed in on Wall Street connections, it got a bit more complicated.

Progressive enough? Clinton pushes back against Sanders

An 'artful smear'?

Clinton directly accused Sanders of carting out a kind of passive-aggressive campaign against her, hinting that she is somehow corrupt because she accepted corporate money.

"And I just absolutely reject that, Senator," she said. "And I really don't think these kinds of attacks by insinuation are worthy of you."

"So I think it's time to end the very artful smear that you and your campaign have been carrying out," she added, saying "let's talk about the issues." The "artful smear" remark didn't seem to land well with the University of New Hampshire audience, though Clinton tried to make the point that, despite the attacks from Sanders, the two didn't really disagree on campaign finance reform. She also forcefully made the case that her track record illustrates she isn't a tool for special interests.

However, it also allowed Sanders to focus on the issue that's propelled him from long shot to top contender: anti-Wall Street populism. And it led to questions about a topic that may not cast Clinton in the best light, particularly with liberal Democratic primary voters: speaking fees from Wall Street firms.

Clinton to Sanders: 'End the very artful smear'

'I'll look into it'

Clinton has come under criticism for being paid hundreds of thousands of dollars for giving speeches to corporations and non-profits. Her answer has been pretty standard: This is what former top officials do; they go on the speaking circuit and make a lot of money giving the wealthy a behind-the-scenes look at major world events.

But when asked at the debate to release the transcripts of those speeches, she said: "I'll look into it," a response that could give a new line of attack to Republicans who have been hammering her about the release of emails from her private email server as secretary of State. It also comes just one day after she said at a CNN forum, when asked why she'd accepted $675,000 in speaking fees to address Goldman Sachs: "I don't know. That's what they offered."

Sanders seized on the opportunity to blast Goldman Sachs, and by implication, Clinton's association.

"Goldman Sachs was one of those companies whose illegal activity helped destroy our economy and ruin the lives of millions of Americans," he said. "But this is what a rigged economy and a corrupt campaign finance system and a broken criminal justice is about."

It's an issue that likely won't go away as this campaign continues in the early voting states and beyond.

Clinton says she'll 'look into' releasing paid speech transcripts

Foreign policy: Experience vs. judgment

It should come as no surprise that Clinton, who ran the State Department, seems more at ease discussing the finer points of foreign policy than Sanders. He nearly acknowledged as much at one point in the debate.

"I fully, fully concede that Secretary Clinton, who was secretary of State for four years, has more experience — that is not arguable — in foreign affairs," he said, before making the point that judgment should also be a key determinant in deciding who should be the next commander in chief, citing her Iraq War vote from 2002. It was an argument not unlike then-Sen. Barack Obama made in 2008 against Clinton. It worked for Obama. Will it work for Sanders?

Clinton was in a stronger position eight years later to dispel the judgment critique than she was in her first White House bid. She noted that she was "very proud" of the fact that "when it comes to judgment, having run a hard race against Senator Obama at the time, he turned to me to be secretary of State." As for the Iraq vote, rather than try to defend her decision, she sought to dismiss the issue as almost a criticism from another time.

"A vote in 2002 is not a plan to defeat ISIS," she said. "We have to look at the threats that we face right now."

Fifth Democratic debate: Highlights from New Hampshire

What a difference a two-person debate makes

After a campaign that's featured Republican debates with as many as 11 on stage, it was clear that having two candidates square off allows for a much more organic conversation, with opportunities to agree as well as disagree. With each candidate having ample speaking time, there was only so much opportunity to rely on practiced catchphrases in response to substantive policy questions.

It also gave moderators much more leeway to ignore the rules and let the conversation progress, rather than having to enforce rules to maintain some sort of parity in speaking times. Will we eventually get a Trump vs. Rubio; Rubio vs. Cruz; Cruz vs. Trump debate? Tonight's Clinton vs. Sanders face-off should make GOP voters hope that, whoever their two finalists are, they're given the opportunity to see that debate.

Clinton, Sanders tangle in fierce one-on-one Democratic debate