In the famous leaked video, Mitt Romney says
My job is not to worry about those people
An equivalent sentence probably is
It is not my job to worry about those people
Some media in my home country have translated it to something roughly like
My job is: not to worry about those people
The difference is that the not can be assigned to "my job is" or either to "to worry about those people. I actually do not know how this difference can be demonstrated by two proper English sentences, so I hope you get the idea.
Question: Can these different shades of meanings be rendered in English just by word order or grammatical particles? Is there any ambiguity in Mitt Romney's statement?