He's attacking the Marriage Vow that Michele Bachmann signed on to this week.
Question 1: will she respond? At least in the release, Johnson doesn't mention her by name, for what it's worth.
Question 2: Johnson specifically defended "women who choose to have abortions" in his release. If he manages to get publicity on this (which is by no means certain; I saw it because Conor Friedersdorf retweeted something from the Johnson campaign, and certainly the very small anti-Paul or lukewarm on Paul libertarian wing of the GOP is paying attention to Johnson, but that's an awful small group), will it push the mainstream conservative candidates toward taking the "Vow"?
Question 3: Speaking of Ron Paul -- I don't really recall him doing something like this during the 2008 cycle, but I could be wrong. Anyone remember?