A group of more than 100 anti-Republican protestors temporarily took to the street outside Fiserv Forum after the debate began.

The group was advocating on behalf of several causes championed by the left, carrying signs advocating for abortion rights, transgender rights, immigrant rights and Black Lives Matter, among other causes.

Some of the signs were more explicitly political in nature, directly targeting GOP candidates.

One protestor carried a sign reading “Down with DeSantis.”

The group cheered, whistled and chanted as they advanced down the street.

“Get up, get down, Milwaukee is a union town,” was one chant that could be heard.

The protestors were accompanied by legal observers.

The group walked down an open street and at one point briefly blocked traffic. The protestors were otherwise peaceful and dissipated soon after they began.

-ABC News’ Allison Pecorin and Olivia Osteen

The candidates came to the debate prepared with answers about abortion – carefully considering their wording, and, in a stark departure from the first half hour, actually answering the moderators’ question on the issue.

One thing the candidates didn’t want to talk about? Climate change. The moderators asked the candidates to raise their hand if they believed human behavior was driving climate change — but that didn’t happen. Instead, DeSantis said he wanted to debate rather than answer a question like “school children.” Ramaswamy chimed in to say “the climate change agenda is a hoax,” drawing boos from the crowd, though it wasn’t clear what exactly they were booing. Christie jumped in to say that Ramaswamy sounded like both ChatGPT and Obama. Haley decided that this was the moment to quote Margaret Thatcher — “if you want something done ask a woman” — though she did answer that climate change was real, putting the onus on China. And Scott used the moment to chide the rest of the field for being “childish.”

— Analysis by Leah Askarinam of FiveThirtyEight

Christie again focused on his record as New Jersey governor when asked about how he'd address shootings and gun violence plaguing the nation.

He accused prosecutors of not arresting violent criminals and said a "President Christie" would appoint attorney general to instruct U.S. attorney to do so.

"We have plenty of room in the federal prisons to lock up these violent criminals and clean up what's going on all across this country and these individuals," Christie said.

During the abortion back-and-forth, Pence claimed that 70 percent of Americans support a 15-week abortion ban. He’s cherry picking the results from one poll.

A 2022 survey from the Center for American Political Studies at Harvard University and The Harris Poll asked respondents, "Do you think your state should allow abortion…?”

Twenty-three percent said up to 15 weeks, 12 percent said up to six weeks and 37 percent said only in cases of rape and incest. That’s 72 percent all together. But answers in surveys vary greatly depending on how the question is asked.

A 2022 Economist/YouGov poll asked specifically about a 15-week ban — 39 percent supported it, 46 percent opposed it. A 2023 PBS NewsHour/NPR/Marist poll asked respondents whether abortion should be allowed up until 24 weeks — 44 percent said yes.

-Aaron Sharockman, PolitiFact

As Republican candidates gear up for the debate, many have specific rituals they’ll be doing in preparation.

A campaign adviser for Haley said she will be listening to music, “lots and lots of music: Joan Jett, Queen, Def Leppard and [the] Go-Gos, to name a few.”

DeSantis has spent today with his wife, Casey, and their three children, though a campaign spokesman offered few details about how the family has spent their time.

Hutchinson posted a photo of himself preparing with notepad and laptop in hand.

“Some last minute studying and prep for tomorrow! It’s important to show up and be ready to answer the tough questions, you deserve nothing less than a leader ready to lead on day one,” Hutchinson captioned the photo online.

Pence will plan to spend time in prayer before the debate, while Scott took a tour of the debate stage, which he posted a video of, along with encouragements from his family, to X, formerly known as Twitter.

Others prepared physically, earlier this week.

Ramaswamy posted videos to X of himself playing tennis and him and his wife doing floor exercises in a gym throughout the lead-up week.

Burgum was playing a stress-relieving pickup game of basketball on the eve of the debate, according to a campaign press secretary, when he sustained an Achilles injury that called into question his ability to participate in the event.

He will be participating, albeit on crutches, per a photo posted to his X account.

-ABC News’ Gabriella Abdul-Hakim, Libby Cathey, Abby Cruz, Will McDuffie and Olivia Osteen