I always hear about the United States impinging upon treaty provisions with Native Americans and was wondering: Has there ever been a "good" or successful treaty that has held up to this day?
As far as I'm aware, most treaties between the US government and the various Native American tribes are still in effect. That's the legal basis for NA sovereignty.
In fact, I remember a few years ago a local (I live in Washington State) tribe wanted to conduct some whaling, and they were able to do it because their treaty specifically allowed such things. That seems like a pretty good indication that there are still treaties in affect, all other examples aside.
I lived in the capital of the Cherokee Nation until very recently and I can assure you that they still stand. Treaty issues still effect the daily lives of thousands of people where I live. As others have pointed out the only reason I and thousands of other Cherokees without health insurance have medical care is thanks to treaties.
Right now the Cherokee Nation is in a legal battle over the Treaty of 1866 after a referendum passed removing the Cherokee Freedmen (descendants of freed slaves that were owned by Cherokees). They are required by a treaty to keep the freedmen in the tribe.
There are at least two other treaty issues that are in legal limbo right now. The Cherokee Nation is trying to find an appropriate case to press its claim on owning the waters of the Illinois River and its tributaries in eastern Oklahoma. The other issue is that they are in a dispute with the state of Oklahoma over whether or not Cherokee citizens inside the five counties that comprise the Cherokee Nation need to purchase hunting or fishing licenses from the state.
Quite a few. The basis for the Indian Health Services is due to treaty agreements.