Eric Cantor stepping down from Republican House leadership is being reported as sending shockwaves through political halls of power, I believe that it is actually not an indicative of things to come but rather a lagging indicator that the GOP's purity test is has the party on a trajectory to obliviation. When elected officials that are willing to compromise about anything are thrown out of the party, such as Arlen Spectre and Bob Bennett, there can be no debate or civil discourse between the parties. As the logjam becomes semi permanant, the voters will continually seek to 'throw the bums out' and as the primaries veer off to a more and more untenable obstruction for obstruction sake position the moderates that were thrown out of the party would either join the Democrats or start their own moderate party like the Likud party in Israel.
Starting a third party with centrist inclination while the Democratic party veering back to a populist left position would be best for the nation, having gradients of political policy among the three parties would give more choice to the electorate for having their voice represented while at the same time dissuade an absolutist purity of ideology due to an alternative viable option in the general election. Though that scenario would be best for the electorate and democracy, the more likely outcome is the lip service paid in campaigns against status quo crony-capitalism hegemony but govern to the whims of Big Business so that every election both Republican and Democratic politicians claim to be the savior of Main Street and bash the elite until they are sworn into office. For example, Barack "Change" Obama who repeatedly stated that you can keep sending the same people into office and expect different results-- then goes hires Clinton's old economic team and Bush's Military-Industrial-Complex team to carry out exactly the same policies.
To rebut the Chief Justice of Supreme Court in his McCutcheon decision, but it is absolutely within the role of government to fix the apparatus of democracy and whether the elected representatives decide that the fix is providing transparency of campaign contributions or restricting only constituents to contribute to campaigns or some sort of public financing of campaigns, to keep our democracy strong and transform an out-of-touch Majority Leader losing an election from shock to expected outcome we need to tackle this as an problem that needs a solution.