(Cross-posted and updated from Obamaism.org)
There have been news reports that Barack Obama is going to try precisely to do that, i.e., make McCain lose his temper; see WSJ, Stand-Ins, Naps Help Debate Preparation,
...Obama advisers, for example, are considering how to provoke Sen. McCain into anger or showing what they say is how out of touch, or old, he is. ...
Is all of that a good idea? Showing that "IsSame McCain" is out of touch with reality, sure; but openly goading and baiting him, or portraying him as the Senate's Grandpa Simpson, could easily backfire. It could even play into many Americans' subconscious racist memes and fears, especially with Obama being far younger and taller than McCain: can Obama afford to look, even momentarily, like he's being abusive, instead of "rising above the old politics" and being thoroughly decent as we know he can be?
(much more below)
Of course, Obama should still be assertive and throw plenty of punches--as long as they're not rabbit punches, and also not perceived as being rabbit punches. And, like Muhammad Ali, he should use wit, grace, and style, "floating like a butterfly" while "stinging like a bee".
If you disagree and think Obama SHOULD goad McCain, provoke him openly, let me know in the comments.
Now as for the Wall Street thing: I wonder if Obama can do some jiu-jitsu on McCain, who is bound to bring up the surge in Iraq and how successful that supposedly was. Possible lines I can think of are, "You were so bold with the surge--so Americans wonder why there's no surge of positive leadership from you on the Wall Street crisis", cf. McCain's reported lack of helpfulness in resolving the crisis. Or, "You say you were all for the surge, but when it comes to doing some surgery on the wounds of Wall Street, you're not stepping up to the plate, and you didn't even want to step up to tonight's debate, Senator. Is that being ready to lead? Does that show experience?", or words to that effect.
Cf. Joan Walsh at Salon noting,
...Now, I trust Obama to be smart enough to tie the current financial crisis to foreign policy -- fairly, not as a stretch, given the global dimensions of the turmoil. But it would have also provided McCain with an opportunity to taunt Obama about his opposition to the so-called surge in Iraq, and to change the subject generally -- and that could potentially be good news for McCain. ...
But why let McCain profit from mentioning the surge? when it could be turned back on him?
If McCain bothers to show up to the debate (UPDATE: he apparently will, unless he changes his mind...flip-flop flip-flop), Obama should be able to do a pretty good job on him, provided that Obama does not lose control or act hubristically himself, and is able to reflect McCain's attacks back onto McCain. --Unless you have a different opinion, which I look forward to reading.