MINNEAPOLIS (WCCO) – Public opinion polls this week are showing the campaigns for two constitutional amendments are getting very close.

But adding the marriage and voter ID amendments to the state constitution that’s been around since 1857 may depend on voters who skip the amendments on their ballots.

That’s because skipping them has the same effect as voting no.

Minnesota politicians win elections all the time without winning a majority of votes.

Mark Dayton? 44 percent

Tim Pawlenty? 46 percent.

Al Franken won with 42 percent and Jesse Ventura was victorious with 37 percent.

All won pluralities, not majorities.

A constitutional amendment? That’s much harder to pass.

Constitutional amendments must be approved by a super majority: A majority of everyone voting in the election, not just a majority of people voting on the amendment.

So if there are 100 voters: 49 vote “Yes,” 47 vote “No,” and four skip the amendments, the amendments fail — it’s not a majority of everyone who went into the voting booth.

But that’s not the whole story. Minnesota’s had a super majority requirement since 1900.

The state’s liquor industry campaigned for, and won, the tougher standard because it was trying to make it harder to add a prohibition amendment to the Constitution.

And it worked. Before 1900 in Minnesota, 72 percent of constitutional amendments were adopted. Since 1900, only 51 percent.

Many voters do skip the constitutional amendments on the ballot.

History shows it takes about 60 percent of voters on Election Day to pass a constitutional amendment.