As for callow, I would have guessed, quite superficially, at some combination of the words 'cad' and 'shallow'. I was a little more off the mark there, as callow does not denote anything so explicitly negative. It just means 'lacking adult sophistication'. The article was describing Obama. The descriptor is somewhat ironic, as Obama comes off as very adult and very sophisticated, at least to me.
You got something on your mind, honkey?
So there. Remember than angry republicans are 'vituperative' and that Obama is 'callow' and you will never forget these two words. Impress your friends or avoid feeling embarassed. Don't walk the same path I did.