Fear fueling Republican extremism - CNN.com . "In our past writings, we have criticized both parties when we believed it was warranted. Today, however, we have no choice but to acknowledge that the core of the problem lies with the Republican Party. "The GOP has become an insurgent outlier in American politics. It is ideologically extreme; scornful of compromise; unmoved by conventional understanding of facts, evidence and science; and dismissive of the legitimacy of its political opposition. "When one party moves this far from the mainstream, it makes it nearly impossible for the political system to deal constructively with the country's challenges."