Cruz and Trump's stalemate
Sen. Ted Cruz of Texas and the real estate mogul have so far tiptoed around public attacks on one another, but they seemed more likely to collide after Cruz gained traction in recent polling, both nationally and in Iowa. But Cruz skirted a direct invitation to question Trump's judgment, and joked about making Trump personally pay for a border wall, the businessman's often-criticized policy proposal.
Trump found a sparring partner in former Florida Gov. Jeb Bush, who told the mogul he could not "insult" his way to the presidency. The two had heated exchanges about Trump's controversial plan to temporarily bar foreign Muslims entry to the United States. They also clashed over their ability to negotiate with foreign leaders.
Bush lashed out at Trump, saying: "Donald is great at the one-liners, but he is a chaos candidate and he would be a chaos president."
Trump and Cruz largely limited their attacks to the so-called "establishment" candidates, like Sen. Marco Rubio of Florida.
Cruz and Rubio have nudged their way toward the front of the polling pack, and controlled much of the conversation Tuesday night. They traded barbs on the expiration of the National Security Agency's legal authority to collect bulk phone data. Rubio supports a renewal of the program.
"We are now at a time when we need more tools, not less tools," he argued.
They also clashed on immigration reform, an issue on which Rubio has taken a more moderate stance than Cruz.
Rubio in particular faced a string of attacks, and largely held his ground.
U.S. military budget
In both the first and second debates, candidates repeatedly pushed for more military funding.
"We need to focus on building a military that is second to none," Bush said.
Criticism largely surrounded cuts to funding during the Obama administration.