The second night of the second Democratic debate featured more arguments over candidates' records and less over their plans, but there still were some meaty policy discussions.

From climate change to health care to immigration, here were some of the highlights.

IMMIGRATION

There was a spirited argument over former HUD Secretary Julián Castro's proposal to make illegally crossing the border a civil offense instead of a criminal one, which he argued would take away a legal tool the Trump administration has used to separate families.

Castro spent a little more time than he did in the first debate last month reassuring that his proposal was not "open borders," noting it would still be possible to remove unauthorized border-crossers and that border patrol officers and fencing would remain in place. "There still will be consequences if someone crosses the border. It’s a civil action," he said.

Former Vice President Joe Biden was unconvinced. "Here's the deal, the fact of the matter is that in fact when people cross the border illegally it is illegal to do it unless they’re seeking asylum," he said. "People should have to get in line."

But the candidates also branched into other areas. Washington Gov. Jay Inslee said he would "boost the number of people we accept" as refugees from countries like Syria. Biden talked up his plan to expand legal immigration, including allowing students with advanced degrees to obtain a green card.

That prompted Sen. Cory Booker, without articulating a specific policy difference, to argue Democrats should not put so much emphasis on education and skills as a prerequisite for immigration.

"That's playing into what the Republicans want, pit some immigrants against other immigrants, some are from s---hole countries and some are from worthy countries," Booker said.

CRIMINAL JUSTICE

Biden talked up his broader criminal justice plan, which focuses on diverting drug offenders to treatment and features $20 billion in grants to states to encourage them to end mandatory minimum sentences and set up crime prevention programs.

Booker, who has his own extensive set of proposals on criminal justice reform and was an author of the First Step Act that passed this year, argued Biden's past support of tough-on-crime legislation made him the wrong person to implement it.

Booker and Harris each noted they would legalize marijuana and tax sales to fund related social programs. Biden's plan would not go quite as far, opting only to decriminalize marijuana.

"We have got to have far more bold action on criminal justice reform, like having true marijuana justice, which means that we legalize it on a federal level and reinvest the profits in communities that have been disproportionately targeted by marijuana enforcement," Booker said.

Jumping off a discussion of the Justice Department's recent decision not to prosecute the New York City police officer who was involved in the killing of Eric Garner, Castro brought up his campaign proposal for police reform.

Harris, addressing the same case, said she would expand the role of the Civil Rights Division, which reportedly pushed for prosecution in the Garner case only to be overruled by Justice Department officials.

"Under my administration, the Civil Rights Division will reign, and there will be independent investigations," she said.

HEALTH CARE

Two candidates were at the center of the health care conversation: Harris and Biden.

In Harris' case, she was making the case for her new plan to transition all Americans to Medicare over 10 years while allowing private insurers to potentially offer plans through the Medicare system. In Biden's case, he was pushing his proposal to add a new optional Medicare-like plan and boost the Affordable Care Act's subsidies to lower premiums, deductibles, and out-of-pocket costs.

Harris said she came up with her new plan, after "listening to American families, listening to experts, listening to health care providers" who raised issues with her previous support for Sen. Bernie Sanders' single-payer bill.

Picking up his prior arguments against "Medicare for All," Biden assailed the Harris plan for still requiring Americans to give up their existing employer plans in favor of a Medicare plan. He suggested the 10-year transition was a way to cover up its long-term cost, citing outside estimates that single-payer plans could cost over $3 trillion a year. Biden estimated his own plan would cost $750 billion over 10 years.

"Any time someone tells you you're going to get something good in 10 years, you should wonder why it takes 10 years," he said.

Harris argued Biden's plan would still leave millions uninsured, while her plan would auto-enroll people in Medicare to close potential gaps. But she also flipped the terms of the debate on employer insurance, arguing that Americans would no longer feel tethered to their work once they got their insurance through Medicare.

"I have met so many Americans who stick to a job that they do not like, where they are not prospering, simply because they need the health care that their employer provides," Harris said. "It's time that we separate employers from the kind of health care people get and under my plan."

She got some backup from businessman Andrew Yang, who said his experience in the private sector convinced him single-payer would help entrepreneurs.

CLIMATE

There was a lot of back and forth on climate, but not much discernible disagreement between the candidates. Inslee, who has put out a detailed $3 trillion-plus plan to rapidly move to renewable energy and electric vehicles and aid communities affected by the transition, accused Biden of not going far enough in shutting down fossil fuel production.

"The science tells us we have to get off coal in 10 years; your plan does not do that," he said. "We have to get off of fossil fuels from our electrical grid in 15; your plan simply does not do that."

Biden countered that he would push to end any subsidies or tax benefits for fossil fuel companies and pointed to his own $1.7 trillion plan to invest in new technology and renewable energy infrastructure. He said he would put special emphasis on diplomacy, where he would look to rejoin the Paris climate agreement and set its goals even higher.

"We will double offshore wind, we will end any subsidies for coal or any other fossil fuel, but we have to also engage the world while we're doing it," Biden said. "We have to walk and chew gum at the same time."

Booker snarked that rejoining the Paris agreement was "kindergarten" given that all the candidates have pledged to do the same.

The one truly unique position came from Yang, who argued that catastrophic climate-related flooding was inevitable and that his plan for a universal basic income of $1,000 a month would help vulnerable communities leave.

"We are 10 years too late," he said. "We need to do everything we can to start moving the climate in the right direction, but we also need to start moving our people to higher ground."