Romney has given three speeches since his convention address, delivering remarks in Lakeland, Jacksonville, and Cincinnati. The combined total of references to welfare in those speeches? Zero.

Also, I spoke this morning with a Democratic source who confirmed that the Romney campaign's television ad featuring the welfare lie is not currently on the air.

So, over the course of about a week, this one transparent falsehood went from being the most potent attack in the Republican arsenal to a lie Romney and his team suddenly didn't want to repeat.

Why Romney has given up the welfare attack, and for how long, is the big question.