Bernie's just said what made George W. Bush so successful. When you have mandate, from the people, you take that mandate and get your agenda done. Anyone who looks to step in the way of that, you make them famous. Bush wiped the Dems in 2002 because of that. Obama is afraid to tell people what his opposition believes in.
This part of politics is actually easy, and mandated if you're going to be the leader of a party. So people can hate me for saying how miserable Obama was at it, but his election is not my first rodeo with politics. You find every senator in opposition and you do opposition research on them. You find out who they are receiving their money from, and you exploit that. You weaken them, and then offer an olive branch or you spread your ether.