Finally the architecture of the G-20 is changing, writes Worldfocus blogger Nina Hachigian, and the major powers are going through experiments in accountability.

The agenda for this week’s G-20 meeting is full, writes Worldfocus blogger Nina Hachigian, but when leaders sit down in Pittsburgh to discuss banking regulation, energy and poverty alleviation, one question will not be on the table -- the question of who should be at the table in the first place.

Richard Haass of the Council on Foreign Relations and Carla Robbins of The New York Times discuss the week's top stories: The G-20 summit meeting, the meeting between President Obama and his Russian counterpart and whether Iran and the United States actually talked this week or not.

Martin Wolf of the Financial Times of London discusses whether the measures announced by the G-20 leaders in London will have a real impact on the global economic crisis.

Reginald Dale, a senior fellow in the Europe program at the Center for Strategic and International Studies, discusses the divide over regulation between France and Germany and the UK and U.S. and whether Russia will respond to President Obama's pledge to "reset" the relationship with Russia.