With the Iowa caucus just over 40 days away, Tuesday's Republican debate showed signs the Republican field is starting to solidify. It also demonstrated the lengths the candidates are willing to go to prove their strength on national security and display more hawkish sensibilities. Clear divisions over defense emerged between Sens. Ted Cruz, R-Texas, and Marco Rubio, R-Fla., as the pair continued to clash with each other on a host of issues throughout the evening.

Listen as the Washington Examiner's Chief Political correspondent Byron York along with Michael Barone consider how the 2016 Republican filed is narrowing to about four top-tier candidates.

Each Friday, tune in for intelligent updates on politics, policy and the 2016 presidential race with Byron York and Michael Barone. Get smart and stay informed with Byron & Barone.

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