The rumble on Thursday night in Houston was fiery at times, with former vice president Joe Biden coming alive to defend his record and push back against his progressive opponents in Sen Bernie Sanders and Sen. Elizabeth Warren. Many candidates had some key moments in the ABC News Democratic debate, perhaps some of the best since the campaign started.

Related: Watch The Third Democratic Debate Video

Here are 6 key takeaways of what we saw down in Houston at the third Democratic debate and what it will mean for the campaign moving forward.

1. Biden fights Warren and Sanders on Medicare-for-all

This battle started off the evening on a rather aggressive footing where Biden was clearly much more prepared to defend his support for President Obama’s Affordable Care Act and much more prepared to go on the offense in attacking healthcare plans put forth by Warren and Sanders.

As CNN notes, Biden came to play, and play hard, on this topic:

Biden was quick to criticize Warren, who supports Vermont Sen. Bernie Sanders’ Medicare for All plan in which private insurance would effectively be ended and all Americans would be enrolled in a government program.

Instead, Biden said, he is offering a more modest proposal that builds on Obamacare by giving Americans the option to buy into a Medicare-style program — but doesn’t require it.

“I know the senator says she is for Bernie,” Biden said. “Well, I am for Barack.”

Warren attempted to defuse Biden’s approach by praising the former president. “We all owe a huge debt to President Obama, who fundamentally transformed health care in America and committed this country to health care for every human being,” she said.

The former vice president went on offense, pressing Sanders and Warren on how they would foot the 10-year, $32 trillion bill for their proposal.

Sanders reminded viewers that he “wrote the damn bill” — which is notable because health care is the rare issue on which Warren does not have her own plan; she backs Sanders’ Medicare for All proposal. And he argued it’s “the most cost-effective approach to providing health care” to everyone in the country.

Warren ducked a question on whether she would raise middle-class taxes to pay for Medicare for All.

Biden’s objective was not to entirely discredit the goal of Bernie’s Medicare-for-all plan, but it was to discredit the logistics of getting the country to that point. First and foremost, the plan would have to make it through Congress, and the price tag, as Biden points out, is quite massive, even for a Congress that likes spending money.

Biden’s attempt to defend President Obama is really the only course of action he has. After all, he spent years defending his Commander-in-chief and defending his signature healthcare legislation, it would look hypocritical if Biden didn’t defend ObamaCare now. The plan wasn’t perfect, Biden admits, but it was the start of moving toward a goal of providing health insurance for every American.

Warren lost some points on her inability to properly answer whether her plan would raise taxes on the middle class, though she and Bernie have both admitted as such. The counter to the fact, they claim, is that health insurance premiums would be paid for under the plan so in offsetting health care costs, a tax increase would cost the average family far less than their health insurance used to. Biden will do his best to focus on the basic fact that taxes would have to go up to support a Medicare-for-all plan, regardless of which candidate is proposing it.

2. Biden’s age becomes a line of attack

For the first time, a candidate chose to use Joe Biden’s age as a point of attack. Former HUD Secretary Julian Castro accused Biden of forgetting something he said just minutes before, and doubled-down on the attack multiple times.

You can see the change on Castro’s face when he realizes he can turn this exchange into a question of Biden’s short-term memory.

Aside from his age, Castro wouldn’t quit in his attacks on Biden, as CNN also notes:

Criticizing Obama over deportations, Castro said of Biden: “He wants to get credit for Obama’s work, but not have to answer any questions.”

“I stand with Barack Obama all eight years, good, bad and indifferent. That’s where I stand,” Biden responded.

The back-and-forth raised questions about what Obama’s legacy really is — and how Democratic voters want to see it furthered. Do they want to elevate his loyal vice president? Or are they looking for what Obama once was: A young, inspirational candidate to lead them into the future?

It’s not clear that Castro qualifies as the latter. His attacks on Biden perhaps weakened Biden but also risked alienating Democratic voters, who largely like all their leading candidates, including the former vice president.

There was a lot of agreement from analysts, and from other candidates, such as Sen. Cory Booker, that Castro’s attacks on Biden started to come off quite harsh and may have hurt him more than they hurt the former vice president. Booker called his attacks a “cheap shot” and lamented the tone they set for the debate.

3. Harris attacks Trump more than Biden

It appears that Sen. Kamala Harris has decided that she won’t risk attacking Biden directly on the debate stage any further and instead decided to focus the majority of her ire toward President Trump. A smart move, to some extent, since every Democrat will appreciate her jabs at the President, but will it help move her poll numbers?

ABC News notes that this was a key strategy change for Harris:

“I have a few words for Donald Trump,” Harris said, turning to speak directly to the camera. “What you don’t get you is that the American people are so much better than this.”

The California senator added that her campaign is focused “on our common issues, common hopes and desires” and that she will work to unify the country and turn “the page for America.”

“And now, President Trump, you can go back to watching Fox News,” Harris said after calling out the president.

And later in the debate, amid a fiery discussion on Medicare for All, Harris again used her time to address the president. “At least five people have talked, some repeatedly on this subject, and not once have we talked about Donald Trump,” Harris said. “So let’s talk about the fact that Donald Trump came into office and spent almost the entire first year of his term trying to get rid of the Affordable Care Act.”

As ABC rightly points out, Harris’ address to the President was an attempt to bypass the primary and give voters a taste of her attacks against Trump in the general election. The question is whether or not this strategy is helpful. Do Democratic primary voters want to here jabs and jokes about Trump? Sure they do! However, is that a platform to build a campaign on? That’s a debatable point. Only time will tell if this strategy change will bear fruit in terms of digging Harris out of the polling basement where she’s been stuck for many weeks now.

4. President Obama’s legacy wins praise, not scorn

In both of the prior debates, the legacy and tenure of President Barack Obama took a lot of criticism, some of it by way of criticism against Joe Biden. There were points where some candidates decided that Obama was a terrible Democratic president and went all-in attacking his record on healthcare and deportations. Some key Obama advisors and former aides sent out warnings at the time back in July, urging the 2020 Democratic contenders to show more respect and lay off the popular Democratic president.

As the Guardian notes, this time around was quite different:

One clear winner of tonight’s debate: Barack Obama. Candidates such as California senator Kamala Harris and Castro started several answers by applauding the work done by the former president’s administration – which was quite a contrast from the second debate, after which Biden complained that some of his opponents were disparaging Obama’s legacy.

It wasn’t just Harris and Castro, Elizabeth Warren also praised President Obama’s attempt to overhaul healthcare, she just thinks he didn’t go far enough. There was clearly an effort by candidates to spend less time attacking the record of President Obama, even if they want to attack Biden, and spend more time promoting their own plans as the next logical step in Obama’s legacy.

5. Andrew Yang offers free money to supporters

Andrew Yang’s opening statement was one of the light-hearted moments of the night. As part of the push for his Universal Basic Income plan, Yang urged supporters to go to his website and explain how an extra $1,000 a month would help them. Yang’s campaign would then pick 10 winners with the best stories to begin receiving an extra grand every month as an example of his plan.

The other candidates on stage laughed at Yang and the moment seemed very disrespectful:

Buttigieg’s retort was quite smarmy, and I think it speaks to how most of these politicians view Yang as a candidate. In their view, he doesn’t belong on that stage, much in the same way Donald Trump never belonged on the Republican stage back in 2015-2016. The two are not at all comparable – Trump and Yang – in their style, but they are comparable as political outsiders having never held prior office. Yang speaks to a strain within the Democratic Party that would like to see some personalities from outside the world of politics bring in fresh ideas to Washington. His UBI plan may never come to fruition, but he is polling better than a lot of his competitors on stage. They should all show more respect to him moving forward.

6. Beto takes pushes things to the extreme

Beto O’Rourke, having re-launched his campaign multiple times now, has taken up the mantle of being the most passionate progressive in the field. Not only does he want gun control legislation, but he also wants outright gun confiscation and he’s not afraid to scream it.

As CNN points out, Beto has positioned himself to be the strongest on the issue of gun control with the hope that it will give him a better position and make his colleagues appear weaker on the issue:

O’Rourke’s comment positioned him as a leader in the party’s push for gun control (to the chagrin of New Jersey Sen. Cory Booker, who had advanced a similar proposal earlier).

That’s right where O’Rourke wants to be, in the wake of the early August mass shooting in his hometown of El Paso that he has said changed him as a candidate. And it was teed up by other Democrats, including Biden, California Sen. Kamala Harris and Castro, who praised him for how he’d returned home to try to help El Paso heal.

Another big moment for O’Rourke came at the end of a riff on racism, when he said of Trump: “We have a white supremacist in the White House and he poses a mortal threat to people of color across this country.”

It’s not just guns, as you can see, it’s also the most extreme characterization of President Trump as Beto can muster. Most of the Democratic field calls the President “racist” or accuses him of putting out “racist rhetoric.” Not Beto. According to the former Congressman, President Trump is an out-and-out “white supremacist.” The calculation here, on Beto’s part, is to simply go as far as he can to outflank everyone else on stage with how dire he sees the country under Trump. It isn’t a question of policy differences, according to Beto, it’s framing the campaign of good versus evil. Will Democratic voters agree with this push or is Beto walking down the wrong path? Again, time will tell moving forward.

Mostly solid performances all around

All-in-all, each candidate had a pretty solid night. There were no serious takedowns, as witnessed in prior debates, and there were no serious gaffes either. Castro’s attacks on Biden directly were about as personal as things got, but they were early enough in the three-hour event that they were mostly forgotten by the time other policy issues rolled around.

Biden was solid proved that when he’s under the gun, he can still fight with his competitors and fight as a debater. Warren was strategically careful not to attack Biden personally, and not to impugn his integrity to avoid mistakes made by Kamala Harris which backfired.

Sen. Amy Klobuchar and Sen. Cory Booker also did well, but they were mostly inconsequential in the discussion. Their performances were solid, but not to the point where they are going to drum up any major support moving forward. South Bend, Ind. Mayor Pete Buttigieg also turned in a solid performance, but probably nothing to move the needle.

The next Democratic debate happens on October 15-16 in Ohio. Follow the Democratic debate schedule for the latest on each event.