Barack Obama, the US president, is preparing to visit Latin America saying he wants to forge new alliances across the continent. But can the US rebuild influence in a region it has lost over the past decade?

Obama is travelling to Brazil, El Salvador and Chile where he is expected to make a Cairo-style speech reaching out to the people of Latin America and urging a new era in ties with Washington.

But observers say that may be difficult given the history of US involvement in the region where it has been accused of toppling democratic governments and supporting military dictatorships.

Discussing the issues will be Kevin Casas-Zamora, who served as Costa Rica's vice-president as well as its minister of national planning and economic policy, and Michael Hardt, a Marxist political philosopher best known for his book Empire.

You can join the conversation. Watch the show live on Tuesday, March 15, at 1930GMT. Repeats can be seen on Wednesday at 0430GMT, 0830GMT and 1430GMT.