I hope I never get so compromised that I decide to vote for something that furthers my personal interests even though I know it will be bad for the country.This remark is not as open-and-shut as it seems at first reading.
According to the Declaration of independence, governments are created by individuals in order to to secure their divinely endowed rights. Therefore, only on rare occasions should (what I believe is) the collective interest be compelling enough for me to override my personal interests.
In fact one might argue that sovereign individuals should always vote their self-interest and leave it to their representatives to reconcile the inevitable and legitimate conflicts. I do not take this position, but IMHO it has consistency and merit.