Ramaswamy introduced himself to a national audience from center stage, arguing that an outsider is needed to move America forward.

"First, let me just address a question that is on everybody's mind at home tonight: Who the heck is this skinny guy with a funny last name and what the heck is he doing in the middle of this debate stage? I'll tell you, I'm not a politician. Bret, you're right about that. I'm an entrepreneur," Ramaswamy told co-moderator Bret Baier.

"Now is our moment to start running to something to our vision of what it means to be an American today. If you have a broken car, you don't turn over the keys to the people who broke it again. You hand it over to a new generation to actually fix the problem. That's why I'm in this race, and we're just getting warmed up."

In his response on how to steady the economy, Christie pointed to his record taking on debt in New Jersey and argued he could do the same in to "fight waste" in Washington -- invoking a cut-the-spending mentality that has long been popular among conservatives but became less prominent with Trump's rise, as he focused on other initiatives.

"We cannot sit by any longer and allow the kind of spending that is going on in Washington," Christie said. "Every dollar they spend is a dollar that these people are not allowed to spend on their children and grandchildren. It is robbing our country and it is wrong."

Scott also jumped on government spending as a major problem, touting his votes against legislation by Democrats.

"Over the last several years, I've had an opportunity to vote against spending package after spending package after spending package," Scott said. "And we also need to understand is that Joe Biden's Bidenomics has led to the loss of $10,000 of spending power for the average family."

Interesting early questions by the Fox News hosts. DeSantis got to go first, understandably, and he didn't face any questions about his tenure as governor. By comparison, when the hosts turned to Christie and Scott, they faced questions about state debate in Christie's case and Scott's voting record on spending bills. Both seemed caught a little off balance by actual scrutiny of their records.
-Analysis by Geoffrey Skelley of FiveThirtyEight

Interesting early questions by the Fox News hosts. DeSantis got to go first, understandably, and he didn't face any questions about his tenure as governor. By comparison, when the hosts turned to Christie and Scott, they faced questions about state debate in Christie's case and Scott's voting record on spending bills. Both seemed caught a little off balance by actual scrutiny of their records.

One challenger to Trump has surged ahead — in ad buys, at least. Scott announced an $8 million ad buy this month. The bulk of that, $6.6 million, will go toward TV advertisements in early primary states Iowa and New Hampshire, according to the Washington Post. That’s on top of the $40 million ad buy planned by a super PAC supporting Scott that was announced last month.

Trump and DeSantis, the two front-runners, had dominated in early ad spending. But challengers like Scott have stepped up as they’ve tried to qualify for debates and raise name recognition in early voting states. Super PACs supporting Haley and Burgum have also increased spending recently. Stand for America Fund, Inc., which is aligned with Haley, spent $2.3 million on ads so far in August, while Best of America, which backs Burgum, has spent $2.1 million, according to reporting from NBC News.

Meanwhile, Trump-supporting PACs have spent millions on the former president’s legal fees as the number of indictments filed against him has risen to four. That will leave less money for spending on ads going forward, but Trump remains the top campaign fundraiser.

-Analysis by Monica Potts of FiveThirtyEight