Clues to Christian Bale's on-set meltdown can be found in 'Terminator Salvation'

Christian Bale's rant against the cinematographer who stepped into his sight lines during the filming of Terminator Salvation may have been unforgivable but it is understandable, especially after you see the pounding and lugubrious finished film.

Some actors gas on about dates and sports or crack abysmal jokes but click into character as soon as the director calls "Action!" Others live their characters even during lunch. Early on, Bale received tons of admiring press for being one of the latter. He even transformed his physique in alarming De Niro-like fashion, shedding over 60 pounds to play the sleep-deprived protagonist of The Machinist.

Is it that hard to imagine how he leaped from life-or-death make-believe to real-life over-reaction? John Connor in Terminator Salvation is a creature with mammoth will power.

If he isn't delivering death-blows to mechanical behemoths he's delivering radio exhortations for all surviving humans to join the Resistance -- and ultimately to follow his own commands and not those of the official leadership.

It's a pummeling performance for the audience, with none of the grace, shading and gallantry Bale has brought to previous roles. But it must have been grueling for him, too. This character is 100 percent perspiration, not inspiration. All the actor has going for him is his power of concentration; as John Connor he must be single-minded on a titanic scale. The fate of the Earth rests on his furrowed brow as well as his broad shoulders. How could an actor of Bale's urgency, in this role, not snap now and then?

If he'd have given himself a heart attack instead of tongue-lashing the cinematographer, fans might be mourning him the way Heath Ledger's did when they said he died because he over-committed to the role of the Joker in The Dark Knight (starring, of course, Bale).

The TV-entertainment and tabloid culture that's spread like kudzu with the rise of the Internet and 24-hour cable is supposed to attack individuals and then move on, so that a Britney Spears can go from wash-out to star reborn in months. But sometimes the hits stick, especially to more substantial artists or entertainers who can't explain themselves too easily. Nick Nolte's mug shot remained a default laugh-getter for late-night comedy hosts. No one has pointed out that when he looked like an unwashed street person in a fright wig, he was playing the mad-scientist father of the Incredible Hulk.

Nolte has a safe spot in movie history as one of the great American actors of the last century, able to pack intensely physical roles with volatile combinations of humor, rough nobility and pathos, whether in Who'll Stop the Rain or Under Fire or 48 HRS. Bale has yet to pull together quite as impressive a track record.

But he was touchingly chivalrous in The New World, and he brought 3:10 to Yuma haunted, deep-rooted expressions that cast odd shadows in the wide-open spaces. Bale has been disappointing in the self-serious new Batman series. He seems to have taken to heart Jack Nicholson's famous advice to Michael Keaton: let the costume do the acting. The saddest irony would be if audiences thought his dour Batman and John Connor and his viral on-set rant represented the full scope of his emotions.

Happily, the next time we'll see Bale is as Melvin Purvis opposite Johnny Depp's John Dillinger in Michael Mann's Public Enemies. If that movie lives up to its credits, Christian Bale jokes will finally be passe.