I'm not down with that

As you all know, the election is coming up on Tuesday. Here in California, voters will also be asked to vote on several propositions on the ballot - an attempt at government by direct democracy rather than having the legislature do its job.
One such proposition is Proposition 8, which would change the state constitution to define marriage as only between a man and a woman.
Since the courts here pretty much gave a green light to gay marriage, this is probably the last weapon in the arsenal of those who oppose gay marriage.
I have a huge problem with this.
My understanding is that a constitution is written up to limit the power of government.
What we have here is an attempt to amend a constitution to restrict the liberties of the people.
See the difference?
Whether you care for gays getting married or not, using a constitutional amendment as a bludgeon to smack down folks you do not agree with can NEVER be excused.
That way lies peril.
Life, liberty and the pursuit of happiness does not come with an "only if you're straight" qualifier.
I am a married Christian man who finds the concept of attraction to a member of my own sex incomprehensible, but that gives me no right to use government to discriminate against homosexuals. They do me or mine no harm by existing, and they certainly do not violate the sanctity of my marriage. Given current divorce rates (especially amongst Christians!) us straights are doing that just fine all by ourselves.
As for it being taught in public schools, well there are choices - this is America, after all. We can send our kids to private school, or even home school them ourselves if we dislike the curriculum enough. Better yet, as parents, since we are the primary influence in our kids' lives,we can teach our children and show by example ourselves the life lessons we want them to learn.
You may not agree with the homosexual lifestyle. You may not like it. You may even hate it. What you must do though, is think very carefully about using the power of the government to restrict the liberties of a particular group in our society, if only because the next one up on the block might be yours.