Rasmussen: McCain Leads Obama/Clinton March 20,2008 The Rasmussen Reports daily Presidential Tracking Poll for Thursday shows John McCain's lead growing against both potential Democratic opponents. McCain currently leads Barack Obama 49% to 42% and Hillary Clinton 51% to 41% margin. Poll: Convention lifts McCain over Obama 9/8/2008 McCain leads Democrat Barack Obama by 50%-46% among registered voters, the Republican's biggest advantage since January and a turnaround from the USA TODAY poll taken just before the convention opened in St. Paul.