“Rubio is able to play in both lanes,” a Rubio ally countered. “He is an anti-establishment champion who took on the establishment in 2010 and won. But at same time he’s able to speak to more mainstream conservatives and pull votes from both wings. That’s the big crux, especially given fact that both have strong conservative voting records. Cruz is stuck pulling from one lane of voters.”

The Cruz campaign believes the Texan fits the mold of political outsider that Republican primary voters want better than Rubio does. Cruz supporters tout his superior third quarter fundraising, claim a better grassroots ground game and the advantage of the Southern states, including Texas, voting as a bloc on March 1. They also insist that Rubio is vulnerable for negotiating the bipartisan, comprehensive immigration reform bill that cleared the Senate in 2013.

The Rubio campaign believes the Floridian appeals to more Republicans than Cruz. His ceiling of support is higher because he can attract votes from across the ideological spectrum of the party. Rubio supporters say he is sharper on foreign policy, and relates better to average, middle class Republicans. They also contend that Rubio has been fully vetted, but that Cruz has yet to endure the intense scrutiny that comes with being a front-runner.