Republican Presidential candidate Mike Huckabee struck back Monday after US President Barack Obama said that the former Arkansas governor's comments comparing the Iran nuclear deal to the Holocaust "would be ridiculous if they weren't so sad."Huckabee defied criticism of his statement that Obama was "marching Israelis to the door of the oven," saying Monday on Twitter that "what's 'ridiculous and sad' is that @POTUS does not take Iran's repeated threats seriously."The Republican presidential candidate said that "for decades, Iranian leaders have pledged to 'destroy,' 'annihilate,' and 'wipe Israel off the map" with a "big Holocaust.'He vowed that "Never again," would be the policy of his administration."I will stand with our ally Israel to prevent the terrorists in Tehran from achieving their own stated goal of another Holocaust," Huckabee added.