It's interesting how someone like Peter Garrett, who commanded quite a bit of credibility and respect before entering politics, has come a cropper in recent times.
It seems that sometimes it is more productive for some people to stay out of the cauldron than to enter the fray and do something amidst the constraints of political realities.
Can anyone name a personality - national or international - who in recent times rose to an elevated position and still retained widespread respect and credibility. Nelson Mandela springs to mind, but I'm having difficulty thinking of anyone else.

I think the lesson here is that he might not have cared about the environment THAT much.

The difference between a rockstar who complains about something and an actual Minister relevant to the field is that the while the rockstar makes money by whining alone by people who really can't tell the difference, a Minister actually has to put his/her money where his/her mouth is and do something about it if they (or their party) actually cared so much to begin with.

Poirot,

There's Ronald Reagan and Arnie Schwartzenegger who reached prominence. Not so sure what the credibility and respect indices for these two are though.

I think Garrett's a well-meaning person, but is constrained by the political reality as you say. He probably thought he had done as much as he could from the sidelines and he'd give politics a bash. It was a great coup for the ALP as they rolled out their swag of celebrities to take on Howard and won.

But I suspect Garrett will come off second best in the relationship. You can't really have two masters and it's hard to be at the top of two completely different activities like entertainment and politics. My guess is it will be a case of "easy come, easy go" in his political career.

Poirot
I am also having trouble thinking of an example.

Some actors like Clint Eastwood and Charlton Heston got into politics at a local level I think but don't remember if they remained true to their ideals. Heston is/was a bit of a gun nut, and was involved with the pro-gun lobby and I think he remained true to those principles (if one could call gun ownership a principle).

The reality is in politics one has to sometimes accept compromise and weigh other factors with environmental concerns.

It is easier to be a committed unwavering environmentalist-rockstar when you don't have any other obligations or a duty to listen to all sides of a debate.

Garrett may have thought he could have some influence even if the reality is his own personal environmental aspirations may not be fulfilled.

Yes, Pelican, it is most difficult if we confine ourselves to actors and musicians. But even if you broaden the criteria to anyone that was seen as larger than life prior to their entry into the political arena, (like Nelson Mandela) it is still hard to come up with someone whose reputation wasn't damaged in one way or another.
On the subject of famous musicians, someone like John Lennon was very influential in his way, and had the sense to try and influence opinion by utilizing his fame - I doubt if he'd be held in such high esteem if he had entered the political fray.

I always wonder why people didn't laugh at John Lennon but everyone laughs at Bono. And no I'm not saying people shouldn't laugh at Bono.

I think Imran Khan has made the transition very well.