Before long, President Obama will announce his nominee to replace retiring Supreme Court Justice David Souter. But as the speculation swirls, conservative activists are sending a clear warning – to Senate Republicans…get tough with this choice or face an electoral backlash. So why is this warning coming before we even have a nominee? Which of the people believed to be on the short list is considered the most activist? And what will happen to senators who rubber stamp a liberal activist judge? We ask Scott Wheeler, executive director of the National Republican Trust PAC.