[There is some question as to whether this bill was actually passed by the Missouri House on May 4. The official Missouri legislative web site says no. There are at least two bills of this nature pending, and we'll just have to wait until something definitive shows up.]

Missouri House passes “birther” bill
Just when you thought the birthers had gone the way of bell-bottom jeans and leisure suits, Missouri steps in front of the speeding train of national opinion and passes a bill requiring candidates to prove their citizenship.
ColorLines reports that the Missouri House just passed HB 121, whose purpose is said by one supporter: to keep illegal immigrants from taking over the White House. One can only wonder if he is referring to what some birther blogs call the “Resident of the United States.”
The relevant section reads:
115.399. 1. … the state committee of each established political party shall certify in writing to the secretary of state the names of its nominees for president and vice president of the United States. Such certification shall include proof of identity and proof of United States citizenship for each nominee.
[Emphasis in original indicates addition to existing law.]
This provision was inserted by committee in an otherwise routine change to election law. I don’t really see a problem with that. But really, these birther bills seem so retro.