Hugh Hewitt recently did a wonderful takedown of Obama's rhetorical style which you really ought to listen to. It's funny, but also extremely incisive. Bottom line: most of the time Obama has no idea what he's talking about.
Go here. The clip you want is number 29, hour 2 of the May 20 show (clip number 28, which is hour 3, is titled 'Obama audio' but it's clip 29, 'Dean Barnett', that you want).
The essence of Hugh's analysis starts at around 7 minutes and lasts about 3 minutes, but you should listen from the start to get the context, and listen to the rest of the hour, and hour 3, if you have the time.
Someone with more time and expertise than me needs to put this on YouTube, with a slideshow of shots from Obama rallies.