Under normal circumstances they'd have a point. Under normal circumstances a democracy has a party in power and an opposition of one or more parties. Under normal circumstances there's a palpable difference between the party in power and the opposition.
When in American history has this been true? In fact, in the darkest and most fragile of times, Americans have consistently rejected radical political or economic solutions to crisis....
In the early Republic, when political tensions in many ways were higher than they are today, when our institutions were new, and change could have come easier, radical reorientation was rejected, and an economy and tradition based largely on the English model was adopted. Hamilton and Jefferson were mortal enemies, their contest centered on the type of country we would become - one based on manufacture and market forces, or one, more romantic, based on the virtous agrarian. Hamilton won that contest and is largely responsible for the American nature of our economic structure. Even Jefferson, as early as his Presidential years had largely made peace with the new structure.
In the 1830's when the power relationship between branches of the governemnt were still being defined, Andrew Jackson, clinging to the Jeffersonian notion of an economy based on the yeoman farmer, and through unprecedented use of the veto power, killed the Second Bank of the U.S. on constitutional grounds, and on the grounds that the institution represented a dangerous conglomeration of economic power in the hands of elite easterners, echoing many of the same criticisms we hear today about runaway corporate power. The resulting restriction in credit, threw the country into a serious depression. Jackson won the fight, and killed the bank. It had the lasting affect of increasing executive power, but it did not reorient the basic nature of our economy or our political system. The Federal reserve system was eventually formed, and it hardened the nature of the two party system.
The Civil War might not only have ripped apart our country, but its basic political and economic institutions; it did not. In the subsequent economic turmoil, with the South transformed into a third world economy, juxtaposed against an increasingly prosperous north, populist movements gained some traction, but fizzled out, the American people again rejecting radical political or economic change.
The era of the robber barons who took that prosperity to excess, killing workers rights and starkly increasing the distance between rich and poor, followed up by the severe depression starting in 1893 might also have induced movement toward this type of change, but it did not.
And of course the Great Depression, when corporations ran amuck, and rampant, unchecked speculation threw this country into its largest crisis ever...if there was a time when a fundamental reorienting of our economic and political structure might have taken place, that was it. And indeed the Communist Party and other populist and socialist organizations made local inroads. Huey Long and Father Coughlin gained national followings. But yet again, rather than move us toward a more radical solution, the American people, in their most desperate hour since the founding of the republic, put their trust in existing structures to solve these problems, and Franklin Roosevelt solved them.
The idealogical differences in parties has always been very narrow in the United States, and given numerous opportunities to change that, the American people have rejected a movement to radical solutions to serious problems.
There is no evidence, none, that things have changed. A radical reorienting of the political structure on the order of what you appear to be advocating is not going to happen. Change toward a more accountable government through political reform and a re-balance of power between the citizenry and corporate America is not going to happen by advocating radical, short term change. That course of action will be rejected by the American people as it always has been. It will happen in very small and incremental steps.
In my view, voting for the Democratic candidate moves us in the right direction, no matter how small the step...and that is why I care whether there is a D after the name of the candidate I vote for.