I just checked the Missouri's registration application by mail. I've never voted out of Missouri so was unfamiliar with its requirements.
A couple of check boxes asking if you are a US citizen, place of birth which is (optional), social security number which you can leave blank, drivers license number which you can also leave blank. Then a place to sign where you agree that you are a US citizen.
No where do I see any "proof" of citizenship requirement.
Honestly, am I missing something? or does it appear you only have to sign it stating that you are a US citizen?