As an example, he points out that despite his rhetoric, Reagan increased the size of government and the deficit, and how Bush admitted that he had abandoned the principles of the free market in this policies.
Whatever the differences between the Democratic and Republican Parties, the monopolization and centralization of political power by the Republican and Democratic Parties represents a threat to constitutional republican government: the Democratic and Republican Parties are nothing more than the political organs of narrow factional interests.
Despite their differences, and no matter which of them is in the majority, the result of Democratic-Republican Party government is always the same: expansion of the scope and power of the state, empowerment of corporatist interests, ruling elites and the political class, exclusion of alternative solutions and voices, in short, the reproduction of the Democratic-Republican two-party state and duopoly system of government.
To reiterate, and in conclusion, the Republican and Democratic Parties do not represent the interests of the people of the United States, but rather those of the Democratic-Republican political class and ruling elite. Anyone who still takes a Republican or Democrat at his or her word is nothing but an easy mark. The primary condition of political freedom and independence today is freedom and independence from subjection to and dependence upon the Democratic and Republican Parties, the two-party state and the duopoly system of government.
Further, d.eris addresses the argument that a third party only causes a split that allows "the other side" to win:
But, thankfully, there is only one presidential election every four years. To view all political contests at all levels of government through the prism, and on the model of presidential politics is to undermine the very principles of decentralized federalism and constitutional republicanism. Beyond that, the spoiler argument is nothing more than the first refuge of the loyal duopolist, to paraphrase Samuel Johnson.
As I wrote last August:
If the spoiler argument has any merit, it is to be found in what it reveals about the psychology of disappointed and disenchanted partisans of the duopoly parties. The spoiler argument rationalizes their loss by scapegoating third parties and independents, and thus allows them to avoid assuming responsibility for that loss, while simultaneously robbing their opponents of responsibility for their success.