When the same-sex marriage ban in the constitution reaches the November 2012 ballot, a majority of those voting will have to approve it for it to become law. Occasionally, people vote for people on the ballot, but don't answer the referendum questions. That's as good as a "no" vote.
How often does it happen that a constitutional amendment has failed even though more people voted "yes" vote than "no?"
The last time it happened was more than 30 years ago, when it happened four times on the same ballot. Four proposed amendments got more "yes" than "no" votes, but all four did not get the majority of the total votes cast in the election.
One would've removed the requirement that the Senate approve notaries public, another removed restrictions on the interest rate for and the amount of highway bonds, a third would've established initiative and referendum. A fourth question established a bipartisan reapportionment commission. It got almost 300,000 more "yes" than "no" votes, but fell 6,000 votes short of the majority needed.
Of the 41 constitutional amendment questions on the ballot since 1962, these are the only other ones to fail while still getting the majority of votes cast
1974: A proposal that the constitution be amended when 55% of the people voting on the issue approve it, fell about 10,000 votes short of the required number to be approved. Supporters said it would make amending the constitution easier, but ironically, it would've set a more difficult bar on this particular question.
1966: A proposed amendment would've required legislators to resign immediately upon election to any other office. It fell 80,000 votes short of the required majority.
But getting on the ballot in the first place is a huge step toward being approved. Eighty percent of constitutional amendments submitted to voters are approved.