The first day of the World Economic Forum in Switzerland was dominated by debate over President Barack Obama's proposals to rein in banks and limit their activities. Participants stressed that large banks are an essential part of the global economy and that regulations need to be coordinated on a global level. Barclays President Bob Diamond warned that a backlash against banks would be harmful to the global economy. "You have to step back from the rhetoric. I have seen no evidence ... to suggest that shrinking banks and making banks smaller and narrower is the answer," Mr. Diamond said at the World Economic Forum in Davos, Switzerland.