Tonight as President Obama reshuffles his cabinet we look at the implications for the Arab Spring. A battle over defence cuts is expected but if the main Western powers pull back from the region, what does that mean for the Arab world and the rest of us? We'll be talking to PJ Crowley, the former US state department spokesman about how sustainable Western involvement is. We'll have other guests too. We also have a film about Yemen where President Ali Abdullah Saleh has agreed to step down within 30 days. The US, worried about terrorism, has poured military aid into the country but it is claimed that some has been used by the country's leadership to repress any opposition. And ahead of the Royal Wedding, the American TV networks are getting ready for wall to wall coverage. Why are Americans so fascinated by the Royals?