Veteran GOP pollster Frank Luntz, who conducted the focus group, told moderator Megyn Kelly that her grilling of Rubio on immigration had truly impressed the voters he was monitoring.
"The most important and impactful moment of this debate. It was your challenge of Marco Rubio and watch how well he did on immigration," Luntz told Kelly on her show after the debate.
At the debate, Kelly had pressed Rubio using his pass statements on illegal immigration. As his critics often note, the Florida senator had once backed a comprehensive immigration-reform package that included a path to citizenship before backing off his own bill.
"Haven't you already proven that you cannot be trusted on this issue?" Kelly asked Rubio.
Rubio said matter-of-factly that he would not embrace a hard-line approach like deporting everyone who immigrated into the US illegally. However, he also said he would work through Congress and not implement major immigration-policy changes through executive action like President Barack Obama.
"Absolutely. We're not going to round up and deport 12 million people. But we're not going to go around handing out citizenship cards, either. There will be a process. We will see what the American people are willing to support. But it will not be unconstitutional executive orders," Rubio said as part of Luntz's highlight real.
The focus group reacted by applauding. Several participants told Luntz they became Rubio supporters after watching the debate. They used words like "organized," "confident," "presidential," and "electable" to describe him, when asked to use a single word or phrase.
Luntz also said another Rubio line had sent his focus-group dials "through the roof": a Rubio joke that Sen. Bernie Sanders (I-Vermont) was "a good candidate for president - of Sweden."