Brad DeLong provides an approach to the last 20 years of world history

He calls it: Six Issues for a Panel... and it's US-centric, but worth some thought:

Twenty years ago--with the end of the Cold War--American policy got dammed up:

• It was clear we needed to do something to balance the long-term social-insurance spending promises both parties were making with the long-term tax base, and we haven't.

• It was clear--first for national-security and domestic-congestion reasons, and then for global-warming reasons as well--that we needed to start imposing Pigovian taxes on coal and oil-driven energy use, and we haven't.

• It was clear that we needed to reform America's health care financing system, and we haven't.

• It was clear that America, as the globe's sole hyperpower, had a unique opportunity to build a world in which we could live very comfortably and peacefully once we were no longer a hyperpower or even a superpower but instead only one (if we are lucky) of several great powers--and we haven't.

To this in the past three years we have added:

• A recognition that the "Greenspanist" bet--deregulate finance, rely on financial company shareholders via corporate control to limit moral hazard, and bet that the Federal Reserve can lean up after any elephants that stampede through--was wrong. We need to restructure financial regulation--and we haven't.

• A recognition that the "central problem of macroeconomics" has not in fact been solved. We need to solve it--both in the short run of recovery from this recession, and in the long run of creating a world that is net, whether through global imbalances or other factors, as vulnerable to episodes like this as our world turns out to be.

About these six issues, two questions:

• Which of these six policy issues will--as many of them have been doing--continue to drift, and what damage will drifting do?

• Which of these six policy issues will the Obama administration actually be able to address--and what will be the consequences for the world of how it addresses them?