No, the United States did not require a clear renunciation of citizenship at the time in which these events took place. Due to their illegal practice of polygamy, the Romeny family forfeited their U.S. citizenship by the Edmunds-Tucker Act, the SCOTUS confirmation of that act, and by their sojourn in Mexico as citizens of Mexico for more than five years. It remains to be seen what evidence there is that the Romney anceestors ever applied for and were granted naturalized citizenship after they forfeited their prior U.S. citizenship.
Perhaps they did, but the U.S. voters have a right and perhaps an arguable obligation as diligent citizens to secure such evidence before allowing Mitt Romney on the ballots.
I am pretty certain that the United States government at that time would regard two of it's citizens as citizens until it had been informed that they are not. In absence of information that positively affirms their renunciation of their American citizenship, by the Standards of the United States Government, they remain citizens.
I looked up the "Edmunds-Tucker Act". While I haven't found the actual text of the act, I read a synopsis of it. Nothing in it revokes citizenship, and it is therefore irrelevant to the point at hand. Had the act, Or another one like it, revoked citizenship, then you would have had a legitimate argument. As it is, I see no reason for the United States Government to have changed the citizenship status of George Romney's parents.
If you are going to assert that our Government did change their citizenship status, you need to provide proof that demonstrates such. The default position is that they are Citizens, not that they have renounced.
It remains to be seen what evidence there is that the Romney ancestors ever applied for and were granted naturalized citizenship after they forfeited their prior U.S. citizenship.
They cannot have forfeited their citizenship if the American Government was unaware of it. Such claims fit into the area of unsubstantiated allegations, and as such are not sufficient to reject someone's citizenship. As they did not forfeit their citizenship as far as our government is concerned, they did not need naturalization. If you have evidence of naturalization for the Romney parents, please present it. A quick look at George Romney's history indicates that our Government always considered him a citizen. They placed him on several governmental boards. Not something they would do with a Non-citizen. (Especially during World War II)
Perhaps they did, but the U.S. voters have a right and perhaps an arguable obligation as diligent citizens to secure such evidence before allowing Mitt Romney on the ballots.
The US voters have a right to not be bothered with unsubstantiated accusations. It is beneath the dignity of conservatives to traffic in such claims with no proof. It also damages attempts to attack Obama with the issue by making us all look like we are spewing groundless accusations.