Hello Roy,
1. "from" is the most suitable word - It means, that the features you are talking about has been "based upon" or "taken from" the American constitution.
2. This means Ministers have accepted to take the responsibilty of the outcomes which are arising from the policy. It's like that you are acting on behalf of something. When you say " I'm working FOR the government" you mean to say that you are acting on behalf of the government. you never say I'm working OF the government.
And also the "performance of the Government" means performance that belong to the government, or the actions coming from the Government.
However, to get a broader knowledge of these prepositions you need to read a lot... I hope this helps.
Cheers mate,
Raven