I work within the Democratic Party, not necessarily to kill it, but to greatly diminish its power, for five important reasons.
1) Political monopolies are as destructive in the USA as they are anywhere else. We grew up understanding that the problem with places like Russia and China is that they have a single party, which affords too little political expression and choice. Do not get lost in whatever else may be wrong with those governments. The point here is that we recognize that political diversity is important and, in a world with many different types of governance, we were left comparing ourselves to two of the most restrictive. Our two major parties are far closer, in providing political diversity, to Russia and China, than we are to most of the democratic governments in the world. The two party system is not defined by our constitution, it is an artifact of it. The only way to correct this mistake is to work from within the parties.
2) While our government was created with checks and balances to avoid conflicts of interest and outright corruption, over time those checks and balances have been circumvented and corrupted by both parties. Both parties attempt to hide from culpability.
...I am forced to be a Democrat rather than a Republican because I believe that we are morally and patriotically obliged to provide, at the very least, a social safety net. But this should not keep me from understanding that politicians are reelected, not for what they do for the country, but for the largess that they bring back to their districts. This routine has created a bloated inefficient government. Republicans spend voraciously and stupidly and tell the lie that they are conservative. Democrats suspend critical judgment about wise spending, not because of compassion for all, but because they profit hugely from large government spending. The corruption of the American government is not conspiratorial; it is structural. Design should always be to an appropriate scale our government is one of sprawl.
3) One of the major casualties of our political monopoly is the environment. Much of the largess that our representatives bring back to their districts is environmentally destructive and our most progressive political leaders, in order to get reelected, end up capitulating to large corporations with support for “clean” coal, deep water drilling and so much more. Even some of our brightest pendants on the left fall into, not just justification, but support for the most egregious environmental devastation. Rachel Maddow, who I have a lot of respect for, stands before Hoover dam as an example of the great things that our government can do. Hoover Dam that steals water from the Colorado River - that now never makes it to the Sea of Cortez - to provide neon lights for Las Vegas and orange trees grown in the desert. This is at the cost of unbelievable habitat and environmental devastation.
4) Uncontrolled political spending exacerbates the two party system’s inherent lack of political diversity. This, more so than anything else, has kept us a plutocracy. This is not the fault of the Citizens United decision. That was simply undeniable punctuation. Long before Citizens United political spending had made money more powerful than the democratic franchise. We have a long history of political power being distributed to the wealthy. Both parties have had brief periods of combating this natural tendency. Both Teddy Roosevelt’s Republican Party and Franklin Roosevelt’s Democratic Party helped stem the tide. Now we are overwhelmed with a surge of political money. And how much effort do you suppose that the Democratic Party, who also profit from this flood of money, are going to put into stemming the flow? Despite populist outrage, have you noticed a real effort from the Democratic Party to reverse Citizens United or create publically financed elections that would stop the purchasing of political power?
5) Clearly we would benefit from and expansion of political parties. But this is not going to come from Ross Perot, the Green Party or the Tea Party. It can only happen if structural changes are granted from within the existing political structure. The Democratic and Republican Parties are about as likely to create those kinds of changes as Wal-Mart is to subsidize Target. These changes are going to have to be forced from within both parties by people who understand the need to reduce the influence of the party that they currently support. This is not an easy sell. But what is the alternative?
There are many other reasons to work from within the existing parties to create latitude for expanded political diversity. Our current political monoculture is unsustainable and likely to collapse if unreformed.