While many viewers were fixed on the ongoing political spectacle that is Donald Trump during Tuesday's Republican presidential debate, Ted Cruz and Marco Rubio only had eyes for each other.
The two first-term senators - one from Texas and the other from Florida, both the 44-year-old sons of Cuban fathers and both rising conservative stars in the party - made it evidently clear that they see the other as the primary obstacle to securing the nomination if Trump, the current front-runner, falters.
As such, they engaged in an arm-wrestling contest for most of the evening, sparring on Middle Eastern policy, national security and immigration.
“The Cruz-Rubio battle is now a defining dynamic in this race,” said Ford O’Connell, a Republican strategist.
Both largely left Trump alone - and in fact, when Cruz was invited by debate moderators to attack the real estate mogul, he demurred.
But Cruz had no such restraint when it came to Rubio. Among other criticisms, he accused him of being soft on immigration policy because he helped craft a comprehensive reform measure in the Senate.
A win by Cruz in Iowa could severely damage Trump’s bid, as the real estate mogul’s political message is largely grounded in his current dominance of opinion polls. It could also hand Cruz the kind of momentum that could derail Rubio’s bid to be the candidate around whom anti-Trump voters rally.
“They’re (both) trying to reach as wide a swath of non-Trump voters as possible,” O’Connell said.