I met a Hobbit the other day. Actually he turned out not to be a Hobbit at all but I wanted to grab your attention. And see - it worked. His email 'Hobbit actor seeks advice' had grabbed my attention, so of course I had to say yes.

We met in a suitably warren-like club in London's theatre-land. He's going to be in Peter Jackson's prequel to the Lord of the Rings trilogy, which starts filming in New Zealand later this year. He'll be playing the adviser to a powerful political figure. He'd read the diaries I published after my time advising Tony Blair and wanted to know what makes politicians and their staff tick.

There's no quick answer to that and two hours later we were still talking. He was asking the kind of questions people in politics rarely ask themselves but probably should. What drives them on? Is it just ego? Is power an addiction? What makes a good leader? Why do so many careers end in failure? How do you tell a Prime Minister that he's wrong?

He was especially interested in the personal side of it. He's an actor after all. The public generally have a very low opinion of politicians but, he asked, do genuinely good people choose it as a career? The truth is that they do. And more often than you'd think. They usually have to make compromises, balance the achievable against the ideal, settle for less than they'd like in order to make progress. And the higher you get, the more compromises there are. A cynical and intrusive media will question your motives and delve into your personal life. You can expect little credit for your successes and plenty of criticism for your failings. In fact, it amazes me that talented, genuinely committed people still go into public life at all, but they do.

Sometimes actors can convey the good side of politics better than the politicians themselves. Just look at The West Wing, I said. In real life there are few real heroes and not many villains. But there are a lot of people at least trying to do their best. It's probably the same the world over, I suggested. Maybe even in Hobbit-land. This is Lance Price for CBS News in London.