Kenneth Rogoff is the former chief economist at the International Monetary Fund
"Setting up an agenda leading to the creation of a new global financial regulator or, at least, a new treaty governing global financial regulation, is the single most important agenda item the leaders could confront at the summit. Absent a vision of what kind of financial system we want to see emerge from the ashes of the current mess, it is hard to see how we can proceed with an effective workout of the many bankrupt banks around the world today.
"The US emphasis on a global fiscal stimulus creates an unfortunate and unnecessary tension. First, European governments have higher taxes and more social guarantees, so that there is already a large automatic fiscal stimulus when output falls. More fundamentally, European leaders rightly question the cost-benefit calculation of spending wildly to fight the recession. Ultimately the debts must be repaid, and many European countries already are facing grim fiscal calculations between the prospective costs of bailing out their own financial system (as well as weaker states in Europe), together with adverse demographics.
"President Obama should downplay this issue. The US is in no position to be lecturing anyone on macroeconomic policy right now. Of course the leaders must take steps to ensure that the worlds poor do not become collateral damage to the financial crisis. The head of the UN is quite right to worry about a collapse of aid in the face of growing fiscal constraints.
"Perhaps most importantly, the leaders should agree not to engage in either trade or financial protectionism, such as the US's recent 'buy American' restrictions on its fiscal stimulus. Trade protectionism, which seemed like a far off concern just a couple years ago, is looming as a major threat as the global recession deepens."