Outside of the Trump-critical wing of the Republican primary — featuring Christie and Hutchinson, with major appearances by Pence — most of the presidential field has tip-toed around Trump, careful not to attract his ire. But in the last couple weeks, some candidates have started taking on Trump more directly, jeopardizing their prospects as his running mate.

Trump was already unlikely to name a challenger as his VP pick. Of the 19 unique Democratic and Republican presidential nominees since 1972, only four selected a running mate who had run against them in the same year’s primary. And Trump is even more prickly about loyalty than his recent predecessors.

Last week, we analyzed the tweets of the six highest-polling Republican candidates (other than Trump) in 538’s national polling average. Until recently, DeSantis had hardly acknowledged the former president, mentioning Trump just once since Jan. 6, 2021. But that changed last week, when DeSantis published three critical tweets about Trump. Scott, meanwhile, has largely kept his social media tone neutral toward Trump, but we did see a rare direct criticism on the stump last week, when he said Trump’s suggestion that he’d seek a compromise on federal abortion legislation was the wrong approach. Haley’s tone toward Trump shifted earlier this summer, from cautious to directly critical.

Tonight could tell us whether these recent instances of criticism are the beginnings of a new trend in which the GOP field actually tries to topple the front-runner.

—Analysis by Leah Askarinam of 538

Everyone obsesses over horse-race polls, but another important data point in the primary is each candidate’s net favorability rating, or the share of Republicans who view them favorably minus the share who view them unfavorably. In a horse-race poll, respondents can only choose one option, but in reality, there are probably multiple candidates they might consider voting for. Net favorability rating gives us a proxy for how many voters might be open to supporting a given candidate, even if they are not currently a voter’s first choice.

Unsurprisingly, Trump is the most popular candidate in the GOP field, with a net favorability rating of +53 percentage points among Republicans, according to the 538 average. But DeSantis isn’t too far behind him at +43 points, indicating that, although he isn’t many Republicans’ first choice, most of them still like the guy. Ramaswamy, Scott and Haley also have strongly positive net favorability ratings, suggesting that they are the five most plausible Republican nominees. By contrast, Pence and Christie are underwater with Republican voters, making it difficult to see how they can win the nomination.

—Analysis by Nathaniel Rakich of 538

After each debate, we are releasing numbers from new polling with Ipsos and The Washington Post that show who debate viewers thought won the debate. But since this is the second debate of the campaign, we have the benefit of getting a month’s worth of new polls to average since the first debate. Overall, the picture remains largely the same — but there are some minor changes in the race for second place.

538’s latest national polling average has Trump at 54 percent of the vote among likely Republican primary voters nationwide. On the eve of the last debate in late August, Trump was polling at 52 percent. DeSantis is in second at 14 percent; he was at 15 percent heading into the last debate. Following him are: Ramaswamy, who rose to 10 percent following the last debate but has since settled at 6 percent; Haley at 6 percent (up from 3); Pence at 5 percent (up from 4); Christie and Scott at 3 percent each; and everyone else at 1 percent or below.

—Analysis by G. Elliott Morris of 538

538’s Galen Druke traveled to Simi Valley, California — home of the Ronald Reagan Presidential Library and tonight’s debate — to explore why an area that was once a Republican bastion voted for President Biden in 2020 and whether Republicans can win it back.

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