DENVER — Two state senators, a Republican and a Democrat, sit down on a dais in a dimly lit conference room at the Colorado Convention Center here and start talking. The two men are friends — they tease each other, call each other “dude” — and they’re sick of partisan fights. So, they decide to try something radical. Each will vote with the opposing party on two of the most contentious issues in American politics: abortion and gun rights. “If we don’t do something different, then it’s the same old script,” the Democrat said. That’s the plot of a short play by New Mexico state Sen. Bill O’Neill…