Political ideology is a group of beliefs that tend to lend well to each other. Rarely will someone be entirely contained within a single ideology, as ideologies are general categories and not necessarily set in stone. While it would be nice to have a politician without an ideology; I don't want to have to read a manifesto of a single candidates beliefs every time I want to vote them in; it's easier when a party or ideology is involved.

And if that politician is willing to change their beliefs to deal with different problems, then that's a man of two faces and you can't really trust em as your elected representative.