Ted Cruz, now locked in a struggle to the political death with reigning campaign champion Donald Trump, faces a make-or-break night at the GOP debate Thursday night. Proving his mettle as a candidate worthy of his post-season position, Cruz has ruggedly endured a sustained week of media battering over Trump’s birtherism blitz, losing little ground. Trump’s all-out offensive raising questions about Cruz’s eligibility because of his birth in Canada – widely held to be a non-issue by constitutional experts — has arrested Cruz’s upward momentum but not caused a collapse. But while Cruz has barely dropped in the polls as...