It seems that every strategic move Republicans make backfires. For example, it is easier to snipe than to lead. Republicans are now responsible for Congress where heretofore they were irresponsible and managed the lowest legislation productivity in history.
Their most significant challenge for 2016 is their own independence. Citizens United put the Republican Party in the position of being a commodity. They have lost control or significance to "Big Money". Independent PACs now call the shots. Perhaps the only question is whether ideologues like the Koch Brothers can influence the nomination process of Republicans or if Wall Street will. At least Wall Street has something other than political extremism and exploitation the Koch brothers et. al. are obsessed with. But, that is slim consolation.
The Republican Party has lost control of its own destiny, until they join in bipartisan legislation to quash Citizens United and go back to their donor lifeline. The Republican rank and file needs to wake up and assert democracy finally, or jump ship and become independent voters. (The new oxymoron is the Independent Party as a concept, let alone as a third Party - independent means independent)
The Republican tent was open to Dixiecrat racists, Christian fundamentalists, and Tea Party extremists who became their base. It seems they are out of control inside and under control outside.