You may be sure this was focus grouped to death: Ann Romney “has never worked a day in her life.”
The most incompetent President in history, with no second term agenda, has nothing else to run on but the politics of division and class war. This is the first major offensive (in many senses of the word) in what will be a continuing attempt to portray Romney as out of touch with the needs of people generally and women in particular.
Meanwhile, Michelle Obama, as I recall, had a PR job at some extravagant salary while her husband was a US Senator which, to the surprise of no one, was left unfilled by anyone else after she became first lady.
The one very good part of this, however, is that it is this more than anything that is likely to rile Mitt Romney. If Obama was looking for an opponent who will go in for the kill as best he can, this is the way to have done it.