I'm pretty sure that you're referring to treaties from colonial times, since taken over by the US. Plus treaties with Canada for tribes that straddle the border.
Of course, US states have treaties with Canada and/or Canadian provinces regarding water conservation, trade, etc. They're technically not allowed to negotiate international treaties, so they use terms like "memorandum of understanding." Nothing stops tribes from doing this too.
And the first cross-border treaty in 150 years between tribes in the US and tribes in Canada was signed last year. (Aimed at restoring the bison.)
But independent treaties in the last century with other countries? Got an example?
Some ground-based software produced output in pound-seconds instead of the newton-seconds specified in the contract between NASA and Lockheed. It wasn't so much a conversion error as a failure to use the wrong units to begin with.
But this was for a one-off application, failing the first time it was used. Flights in Europe would have been using metric on millions of flights now for decades. Even on Boeing aircraft in North America, metric has been in use now for over 30 years.
The Gimli Glider incident - where an Air Canada 767 ran out of fuel during a flight - involved a metric-conversion mix-up.
- But this was a brand-new aircraft type.
- The first jetliner they had using metric.
- And also the first jetliner where they got rid of the engineer. The one whose job it was to ensure that the aircraft was properly fueled.
- And Air Canada never set a policy to cover this.
- A faulty fuel sensor was discovered on the flight before. This was OK, so long as a floatstick measurement of fuel was done. There was a whole series of mistakes and misunderstandings here alone.
- The ground crew guy fueling the aircraft had to convert from the truck's gallons to pounds, then from pounds to litres. He used the correct conversion factor, but in the wrong way.
- He then got the pilot to sign off on it, thinking that the pilot was responsible.
- The pilot saw the correct conversion factor on the paperwork and signed off on it, thinking that the ground crew was responsible.
- The airplane took off with lots of power and a great climb rate - because it didn't have all that fuel weight. But this was a wonderful new aircraft type that had a reputation for just that, so it didn't act as a warning.
This was when metric was first in use, not decades later, and even then the conversion was just one in a long chain of problems that led to a bad day. It wouldn't be a problem today. Especially not in Europe.
The government recognizes tribal nations as "domestic dependent nations"; they do not have full sovereignty equivalent to that of foreign nations. Their position is much like that of US states - they have some sovereignty, but they're still very much part of the US and subject to US federal law.
Their position similar to that of Quebec in the fracking case. Any refusal by them to bow to an ISDS ruling is the federal government's problem, not the investors'.
Quebec banned fracking under the (earthquake-prone) St. Lawrence Valley. But Quebec never signed NAFTA; the federal government did. And so it was the federal government that was sued, and has to compensate investors. Another law by Newfoundland and Labrador led to the federal government being sued and having to compensate investors.
Those treaties with American Indians won't be any problem at all for foreign investors. Because if they refuse to allow the pipeline, it's the federal government that's violating NAFTA's ISDS provisions and the federal government that gets sued.
Corporation suing government of $country in same $country?
Indirectly. The Canadian mining company Lone Star Pine sued the Canadian government for $250 million after the province of Quebec banned fracking. They were able to do so under NAFTA’s investor protection clause, using their American subsidiary.
But usually it's a foreign corporation - or corporations with foreign investors - doing the suing.
Is _this_ supposed to "undermine sovereignty"?
Yes. Without ISDS, countries, provinces and states would be free to pass laws regarding the environment, minimum wage, worker safety, etc.. Now they face massive penalties for doing so. (And I can give examples for all three where this has happened.) At the very least this has a chilling effect on such laws.
It's also a state/provincial sovereignty issue:
Quebec never signed NAFTA; the federal government did. Newfoundland and Labrador never signed NAFTA; the federal government did. The provincial laws they passed that prompted ISDS lawsuits, were laws they always had the right to make. But since they never signed NAFTA, it was the federal government that was sued and had to compensate investors.
With TPP negotiations, while the details are scarce, the federal government has been ensuring that the provinces share liability. You can count on this happening behind the scenes in the US also.
Be thankful that Disney Corporation isn't insisting that its creations ("created" from the Brothers Grimm, A. A. Milne, Japanese anime and other sources) aren't protected for the life of the corporation plus 70 years.
Americans could host their web sites offshore. You know, much like Mitt Romney and friends host their bank accounts offshore. I wonder which will be declared "evidence of criminal activity" first?
Meanwhile, bogus DMCA takedowns have become routine practice. Not so routine, is that some of them have led to bad publicity for the companies issuing them. Unacceptably, some of had to withdraw their takedowns.