This expression appeared in a Wall Street Journal editorial of 19 January 2011:
“President Obama took to these pages yesterday to announce a new executive order to restore “balance” to federal regulation and root out rules that impede job creation and economic growth. If he means it, this will be one of the great policy walkbacks in American history. The rest of us should stay in a Missouri state of mind.”
http://transnotes.blogspot.com/2011/01/translation-trivia-missouri-state-of.html
Missouri State of Mind 