Foreign policy conservatives condemn Donald Trump

Sixty former national security officials signed a scathing open letter opposing Republican frontrunner Donald Trump. They say if he becomes president, America will become less safe. The letter calls Trump's vision of American power and influence "wildly inconsistent and unmoored in principle." Frances Townsend, one of the experts who wrote the letter and former homeland security advisor to President George W. Bush, joins "CBS This Morning" to discuss why they're denouncing Trump.