NORTH CHARLESTON, S.C.- Republican presidential candidates Donald Trump and Ted Cruz firmly asserted their standing atop the GOP race in Thursday night's debate, overshadowing a crowded field of rivals still grappling for a way to overtake the fiery front-runners.
    
The debate underscored that the competition between Trump and Cruz will be rough-and-tumble in the days leading up to the Feb. 1 Iowa caucuses. The candidates tangled over Cruz's eligibility to serve as commander in chief and the real estate mogul's "New York values," with Trump besting his rival with an emotional recounting of his hometown's response to the Sept. 11 attacks.
    
Trump also renewed his suggestion that Cruz may not be eligible to serve as commander in chief because he was born in Canada to an American mother.