Likely Republican voters are pretty split on "sending U.S. military forces to Mexico to fight drug cartels," according to our pre-debate 538/Washington Post/Ipsos poll. 44 percent support the proposed policy, compared with 46 percent who oppose.

—Analysis by Holly Fuong of 538

Some early moments in this debate have involved significant cross-talk and interruptions. Burgum's main two comments so far both came via him jumping in to speak without having been asked a question, which is something a low-polling candidate on the periphery of the stage (and race) might as well do with little to lose. Unlike in the first debate, there hasn't been as much of a push by the moderators to give a short rebuttal opportunity to candidates who were mentioned by another candidate, although multiple candidates have asked for that already.

—Analysis by Geoffrey Skelley of 538

The Trump administration built 52 miles of new primary border barriers — the first impediment people encounter if they’re trying to cross the southern border with Mexico, that can block access either for people on foot or for vehicles — where there were none before.

The administration built 458 total miles of primary and secondary border barriers, U.S. Customs and Border Protection data shows. The majority were replacements of smaller, dilapidated barriers.

The U.S.-Mexico border stretches for 2,000 miles across four states and a variety of terrain.
-Analysis by Aaron Sharockman, PolitiFact

Christie was just asked about his position on a pathway to citizenship for undocumented immigrants. In a July poll by The New York Times/Siena College, 39 percent of likely Republican voters say that they supported a “comprehensive immigration reform bill that provides a pathway to citizenship for all undocumented immigrants” in the United States, while 57 percent opposed such a bill. Support was weakest among Trump supporters (29 percent) compared with DeSantis supporters (48 percent) and voters who say they will vote for another candidate (50 percent).
—Analysis by 538

This is False.

Pence has used this 90 percent drop statistic many times, but has never explained where it comes from.

When the COVID-19 pandemic started, immigration drastically dropped worldwide as governments enacted policies limiting people’s movement. In the U.S., Trump instituted Title 42, a public health policy that authorized the Border Patrol to immediately return most immigrants back to Mexico. The increased use of this policy decreased the use of other programs, including "Remain in Mexico."

U.S. Customs and Border Protection during the pandemic also adopted a new way of reporting migrant encounters. Before the pandemic, it only reported enforcement actions under immigration law; its data during the pandemic includes actions taken under both immigration law and the public health policy. Therefore, 2020 data isn’t entirely comparable to pre-pandemic numbers.

Accounting for challenges in data comparisons, our review found an increase of 300 percent in illegal immigration from Trump’s first full month in office, February 2017, to his last full month, December 2020.

One way to get close to Pence’s alleged 90 percent decrease in illegal immigration is by comparing data from May 2019, the month during the administration that had the highest apprehensions, to April 2020, the month with the lowest enforcement actions in calendar year 2020.

But that’s a severely cherry-picked time period.
-Analysis by Aaron Sharockman, PolitiFact