Mostly because every time a Democrat twitches the Republicans have been crying 'WOLF!!! WOLF!!!' to the point that people just don't care anymore There's no question the Republican party is in tremendous disarray, and they grandstand too much.
I am very disappointed in Daniel Issa. There is a very compelling case of collusion between the White House, the FEC, the IRS, and the IRS chief counsel regarding Conservative/Religious groups. He's had "great cards", so to speak, but has not played them well. He's handled them in very anti-intellectual terms.
About the only Republican I know who can communicate in a sophisticated manner is Rand Paul, but even he will step into the party mud just enough times to look silly.