Actually I think he said our greatest threat was climate change (global warming)
http://www.cnsnews.com/blog/terence-p-jeffrey/obama-climate-change-greatest-threat
statistically, the actual threat to greatest amount of people is probably neither.
i mean, if you take the emotion out of it and look at it from a numbers sense, the fcked up healthcare system, or perhaps alcohol abuse, is a greater threat to americans than terrorism OR climage change. In fact, i'd say JUNK FOOD/ SHITTY NUTRITION HABITS probably is the biggest threat facing Americans.
7,000 americans die every day. HALF of them die from heart disease. Zero % of them die from Climate Change. Tragically, several died yesterday from terrorism. the other causes, alcohol, diabetes, etc, they all rank higher in 'killing americans' than either the liberals cause (global warming) or the repubs cause (terrorism).
So I personally think any politician that claims the biggest threat is anything other than the fcking fast-food drive thru lane, is full of shit. however, given the huge number of full-of-shit voters, I am totally cool with people sticking to the other causes in their emotional yet reason-free rants on the matter.