What I'm looking at is:
http://www.politifact.com/personalities/barack-obama/
The PolitiFact scorecard
True (20%)(121)
Mostly True (28%)(163)
Half True (27%)(158)
Mostly False (12%)(69)
False (12%)(71)
Pants on Fire (2%)(9)
I wouldn't consider a half truth to be a truth. Try telling your wife/gf a half truth and see how that plays out.
And if he didn't want campaign promises to be treated akin to telling the truth, then don't frame them as promises. Frame them as "We will try ...", not "I will". Don't promise what you can't deliver, unless you want to be labeled as a liar. Part of the blame lies with him for his delivery; and part of it lies with the idiots who gobbled it up when clear it was BS from the start.