Does the Fourteenth Amendment effectively repeal the Tenth Amendment?

Let me start out by stating that I am in favor of marriage equality.

Now, with that codicil, let me try to answer your excellent question...

There's no absolutely correct or incorrect answer to your question; it really depends on the way you interpret the constitution. I'll try to summarize both schools of thought.

One school of thought deems that the Doctrine of Selective Incorporation brought about by the case of "Gitlow v. New York (1925)" created a window by which the main rights and liberties of Bill of Rights would be made applicable to the states via the mechanism of the 14th amendment's Due Process and Equal Protection clauses. This group views marriage as a fundamental right and therefore is covered by the EP Clause, and thus enforceable on the states.

But there is another way to look at this...

An Originalist, Like Justice Scalia, would argue that marriage is NOT a fundamental right. It's mentioned nowhere in the document -- directly, indirectly, or even inferentially. This school would maintain that the rights of the states to determine licensing is a sovereign state power, and one which cannot be abridged by the federal government.

Under this interpretation, no one has the "right" to marry. It is a license from the state. And the inherent nature of ALL licensing is that it is discriminatory. We do not permit 5 year olds to obtain driver's licenses, nor do we permit ex-felons from obtaining a license to own firearms, or become licensed locksmiths, etc.

In effect we discriminate; but does that constitute a violation of Equal Protection? Not at all. Since licensing is inherently discriminatory, the court applies a "Rational Basis Test." In short -- "Does it make sense?" Does it make sense not to allow 5 year olds to drive cars, and ex-burglers to become locksmith? Yes, actually, it does.

So, can we make a rational argument to defend the proposition that marriage should be between one man and one woman? Yes, we can. The proposition is rational, and thus the states' discrimination is not a violation of Equal Protection.

But again, I remind you that I support marriage equality. So where does that leave us? Simple -- advocates of marriage equality must convince the states to broaden the interpretation of who may get married. In other words, since it's not mentioned in the constitution, it ceases to be a constitutional right and becomes a political right instead. Thus, the appropriate venue for obtaining that right is not in the courts but in the political system.

The 14th does not invalidate the states' rights to govern and set political limits.

Hope that helps. Cheers.

The States have been losing their sovereignty since the very start. It was happening before the 14th Amendment. In fact, the 14th Amendment was just a little ripple compared to the Civil War. The results of the Civil War took away a lot of the rights of the States. In fact, that's the main thing the Civil War was about - States Rights. The 14th Amendment is just a result of it.

So what is left to the States? Less and less all the time. Even without passing new laws or amendments, the Courts take away the rights of the States all the time, and call it "Interstate Commerce" or "Due Process/Equal Protection". While some of these I agree with the results (some I don't, though), I don't like it being done through the courts. For example, the gay marriage issue, I completely agree with allowing all consenting adults to be allowed to pick and choose other consenting adults they wish to marry. But I would much rather have it done through state legislation than through the courts.

No, of course not.