> If a country wants to do this with domestic software produced by a domestic business

It doesn't really make sense to do that with domestic software and to give imported software a free pass.

> which other country that is a party to this treaty is going to have standing to bring litigation

Why does it need to be a country? The domestic software maker whom the government forces to do something that is not allowed under the treaty should have standing.

For example, there's Russia-Canada income tax treaty. If one of those countries wants to hose me in a way that is contrary to that treaty, I should be able to use it to defend myself. I assume it would work the same way with TPP, but obviously IANAL.