The detente between Trump and Cruz is definitely over

The mutually beneficial campaign detente between Donald Trump and Sen. Ted Cruz (Tex.) came to an end on the debate stage here Thursday.

The two Republican presidential candidates, locked in a tight race to win the Feb. 1 Iowa caucuses, argued over whether Cruz meets the constitutional requirements to serve as president and whether Trump is a trustworthy conservative or is tainted by what Cruz called “New York values.”

Theirs was far from the only battle that broke out in the sixth GOP debate of the 2016 campaign season. Sen. Marco Rubio (Fla.) had intensely personal clashes with both Cruz and New Jersey Gov. Chris Christie. Rubio and Christie are both hoping to emerge from the crowded Republican field as the establishment’s champion against the forces of insurgency that Trump and Cruz represent.

Until recently, it was in both Trump’s and Cruz’s interest to avoid a direct confrontation. Cruz was leery of alienating Trump’s supporters — who might come to him, if the incendiary billionaire were to self-destruct. Trump, for his part, did not consider Cruz much of a threat.