I personally think that Clarke has had it much too easy.
He did nothing, in a relative sense, to get selected for Aus in the first place and, aside from the odd flash of brilliance, he's been very ordinary since he's been there.
My sources also tell me that he has an ego the size of Mt Everest and is not the pleasant young man the media would have us believe.
Yet, despite the above, the great minds of the Aus selection panel continue to reward his incompetence. How, in the name of all reason, they elevated him to no. 4 in front of any no. of better qualified contenders is totally beyond me.
The excuse that his competitors are older is pathetic.
Guys like Martyn, Hodge, Hussey and Love can easily play for another 5 - 6 years
Unfortunately, it's more a matter of whether your face fits.
I've heard similar things about the ego but I don't think he's been unbelievably bad. Certainly his ODI form has kept up so I guess the selectors are waiting for when form partity with Tests resumes. He's been figured out technique-wise (like I remember saying he would be well before his first Test) and on FC stats, it certainly was a gamble picking him. But I'm a great believer that a great gamble is a great risk and if it starts to show signs of not going the way you planned, that you ride out the storm a bit, especially when you can see signs that the investment will be worth it in the end.
The selectors did the same thing with Steve Waugh and if a player is showing signs that they want to improve, working hard in the nets, analysing their performances, etc. then that's what you look for because then you know they're mentally equipped to get themselves out of the form-trough their in. It's when they start slacking off at training, getting out to silly swipes across the line, staying out all night drinking, etc. that you start worrying. From what else I've heard about Clarke, he's good at working on something until he gets it right. He's already changed as a player; when he was first-picked, he was all shots. In England he still played his shots but also ground out a couple of tough short innings when Australia were in danger of collapsing into a huge heap. The slower-ball he got in the second Test put an end to what was a very gritty knock to that point. He did it later in the series too. Those are the signs which are good. If he had tried to knock Harmi out of the ground and been bowled middle-peg, that's the sign of someone who's not in the right headspace. Mark Waugh comes to mind in this instance.
I guess the short version is that although not getting to results and being found-out a bit, Clarke at least looks as if he's trying his guts out to figure out what's going so wrong for him. That's what I personally like to see in any player because I know they'll be better equipped for when the next form problems happen (and they will).
That said, he probably is reaching the point where the patience of the selectors will be stretched a bit. Basically he had a good home series against NZ last year, a not so great one against Pakistan, a pass-mark in England and hasn't started off well in this Test. If, at the the end of the summer, his series average is less than 40, I think the selectors will be taking a good look at whether he should remain in the side.