The only argument one could make on the grounds of values would be against the widespread promiscuity evident in gay culture. While many outliers exist, the prevalence of long lists of partners, massively higher risk of contracting STIs, and the presentation of many folks from the LGBT community in pride parades, do undermine the western value system.
While I don't agree with the idea of forcing them to act any other way, these aspects of gay culture do, indeed, undermine core western values.
One would think, however, that marriage is a commitment that would actually go against the other things I mentioned, as marriage comes with an understanding of monogamy and not sharing yourself with anyone but your spouse.
Let me preface this by asking, what are "American values?" John Stewart made an excellent point on this several months ago when responding to Bill O' Reilly claiming that American values are going down the drain. To paraphrase John, there was a time in our history when blacks were considered property, and the Irish were considered one step up from them. If you wanna go all the way back, the people who settled our country were joyless psychos who didn't believe in music, dancing, or colors. Anyone seen "The Crucible"? Yet when we were fighting for our independence, we fought for values such as equality, anti-aristocracy, and individual liberty. Very conflicting ideals all throughout our history. So which is it? Which of the aforementioned are "American values"? America does not have and has never had an official religion. Christians took good advantage of that fact to use their strength in numbers and just declare their religion the law of the land, in effect showing no respect for the law. Therefore, legally, we never had the right to restrict access to abortion or the rights of gays. Same-sex marriage, to me and to any true American, is more in line with "American values" than anything tea baggers claim. This country was founded on the ideas of equality and liberty, and those are the only "values" we need. Get your Bible out of society, there was no place for it in the first place.
Same-sex marriages do not undermine the American value system. America stands for freedom, equal rights and the pursuit of happiness. Since when does someone's unhappiness undermine the American value system? The only thing that undermines America's values is the lack of equality and treating homosexuals like second-class citizens. Gays should be allowed to marry.
There is no way that same sex marriage undermines the American value system. I really do think that the American value system is based on love and pursuit of happiness. Allowing same sex marriages to occur would greatly boost morale and make LGBT members of our community feel more at peace.
I do not believe same sex marriage undermines the American value system. If anything, allowing same sex marriage would better uphold America's values regarding equality which I find to be an important part of our value system. I do not believe this change effects me much as a heterosexual person but I am glad to see they are receiving equal rights.
Without a doubt, same sex marriage does not undermine anything in the American value system. One could even question whether the American value system actually sexists. Nobody should prevent gays from marrying each other by law or discrimination because everyone deserves to marry who they'd like to be with forever.
I do not believe same sex marriage undermines the American value system. I believe allowing same sex marriage is allowing a basic human, fundamental right. I do not believe it affects the American value system in a negative way, I view it being more beneficial than anything. I would rather raise my child in a country that values equality.