As a libertarian, I’ve long felt that people should be able to form whatever partnerships they want to form, without interference from the government. However, as a constitutionalist, I’ve long felt that that change should be made by the legislative process, not by judicial fiat. In any case, this outcome was so obviously going to happen, I cannot muster much satisfaction or much outrage. I pretty much priced it in long ago.
Ideally, the government should now get out of the marriage business entirely. Let any two (or more) people form whatever relationship they choose, and then let society decide which ones they wish to respect. If not all parts of society make the same decision, that’s fine.
But the progressives are clearly against that outcome. They want everyone to be coerced into respecting same-sex marriages, and indeed into participating in the ceremonies. We’ve already seen bakers threatened with ruinous fines, and we’ve even seen ministers threatened with arrest, for refusing to participate. As the Chief Justice’s dissent observed (p. 28), Obama’s Solicitor General has basically promised to try to revoke the tax exemption of churches that refuse to perform same-sex marriages.
So if there used to be some tension between libertarianism and constitutionalism, there won’t be any going forward.
What happens next? When it comes to social issues, most American opinion always sides against the side they see as the aggressor. Much of America has already decided who they see as the aggressor, but media is key for swinging the middle. Ordinarily, they paint the conservative side as the aggressor, and the progressive side as the victim. They were able to do that for same-sex marriage (“why not let these loving couples get married?”), but it will be much harder when it comes to punishing churches.
POSTSCRIPT: For a particularly bizarre instance of coercion, consider this: A same-sex couple asked a jeweler to make their custom-made wedding rings. The jeweler, who was personally opposed to same-sex marriage, nevertheless made them the rings. The couple were happy with the outcome. However, when they subsequently discovered that the jeweler opposed same-sex marriage, they demanded a refund! The jeweler, having done exactly the work requested of him, naturally refused to refund the money, but he eventually agreed after heavy pressure on online media was brought to bear. So what exactly is a jeweler supposed to do?
Internet Scofflaw 
How farfetched is this scenario?
1. Same sex couple goes to clergyperson with traditional views to perform their marriage.
2. Clergyperson declines.
3. Litigation ensues with final decision that marriage ceremonies are “public accommodations” hence clergy may not decline.
4. Clergy (at least those with traditional views of marriage) decline to perform legal ceremonies at all; i.e., no paperwork will be filed with the state. They perform only religious ceremonies. Want to be legally married? See the local Justice of the Peace for a civil ceremony.
What time frame might we be looking at? 5 years?
The end state of this scenario resembles what I understand prevailed in the Soviet Union.
Not at all far-fetched. There was a dry run of this last year in Coeur d’Alene, Idaho, in which the town told a wedding chapel they would have to conduct same-sex marriages or face arrest. But the chapel pre-emptively sued and the litigation ended with the town backing down.
For now, proponents of same-sex marriage furiously deny any intention of forcing ministers to conduct them, but I don’t expect that to last very long. Remember, not long ago supporters of “civil unions” denied having any designs on marriage per se. I would be surprised if we didn’t see some serious litigation within a year.