It looks like the G20 on Friday will emphasize its new “framework” for curing macroeconomic imbalances, rather than any substantive measures to regulate banks, derivatives, or any other primary cause of the 2008-2009 financial crisis.

This is appealing to the G20 leaders because their call to “rebalance” global growth will involve no immediate action and no changes in policy--other than in the “medium run” (watch for this phrase in the communiqué).

When exactly is the medium run?

That’s an easy one: It’s always just around the corner. Not today, of course; that would be short run. And not in 20 years; that’s the long run.

The medium run is perhaps in 3 years or perhaps in 5 years. It feels close enough not to be meaningless at the press conference, but it’s not close enough to be meaningful.

And--here’s the key--whatever you agree on for the medium-term, you know that the world will change, quite dramatically, 2 or 3 times before you get there. At that point you can say, quite reasonably: But the conditions today are quite different from what they were when we made this medium-term commitment, so we really need to rethink it.

Of course, having the IMF report back every year on progress towards these medium-term goals is equally pointless. This is what the IMF has been doing since 2006 and what it was preparing diligently to do just as the global crisis broke out.

Expectations for the G20 summit are low. But unless and until the leaders take any steps to address our pressing financial sector vulnerabilities, the summit is not worth its carbon footprint.

Remember what the financial experts said at the previous summit (April) and the one before that (November): We can’t fix the financial system in the height of the crisis. True enough, although the opportunity to break the power of the largest players was squandered in both the U.S. and Europe.

So, now the crisis is over--as the G20 heads of government will affirm--where are their efforts to fix the financial system? Please don’t tell me, “that’s what we’re doing, in the medium-term.”

[Cross-posted at The Baseline Scenario.]