It should have been obvious, you know. The Neocons were academics and intellectuals, often quite liberal socially and economically, but nevertheless corporatists, and possessed of a radical approach to international affairs based on a very strong sense of the U.S. economic power and, yes, American manifest destiny. There really was nothing in PNAC that fit logically with Republican conservatism, but there were emotional ties, and the GOP got suckered good by its own brand of penis envy. Then, capturing the revolting Dixiecrats into the GOP was a feather in Reagan's cap, not his idea, of course, but carried out beautifully with that appealing Hollywood voice and practiced Tom Sawyer grown up as proprietor of the general store persona. Knitting the manifest destiny yarn with the racist and fundamentalist evangelical skein was simplicity itself, but neither was really logically compatible with the other, or with the Republican center. It was an emotional marriage, but it was the chance to become a viable political party again, so they took the chance and rolled our dice.
"Big tent" politics is a serious matter. The alternative is third parties, and third parties are not nationally viable, not with our population, not with our traditions, and certainly not with our fairly sophisticated communications. Third parties give opportunity for expression of dissenting ideas, but as a practical matter end up as nothing but spoilers. They syphon off the energy, the discontent, the factions that make "big tent" political parties internally honest. Several of my colleagues here and elsewhere disagree, but the plain fact is that third parties, if they have anything at all to say, either remain small and ineffective or are absorbed into one (or very rarely both) of the two major parties. That the two major parties are often syncretic creates the illusion that the two party system is somehow corrupt and that there isn't a real difference between them. There are plenty of differences, of course, you just have to understand the differences between ideology and politics.
Citizens and citizen organizations have ideas about government and what they want government to do or not to do. The origin of political ideology therefore rests with the people, for it is from them that the logic of program and policy is established. Lenin and Leninism is the reverse, of course, but this is America, a democracy. Ideology creation happens both within and outside the political parties, sometimes in the press, sometimes in the universities, sometimes in local civic organizations and clubs. Ideas contend, the logic of combining programs is eventually revealed and the backbone vertebra of ideology are established. American Liberalism, for instance, has depended on the interactions of five core principles to keep its balance: first, an earnest devotion to Individual Liberty; second, a belief in the efficacy of Progress as opposed to sterile stasis; third, a reverence and heartfelt dedication to the education, health and welfare of our fellow human beings everywhere regardless of their subculture, skin color, or form of spirituality; fourth, a practical Ethic, based on Enlightenment principles and a distillation of the ethics found in major world religions; and, finally—but not less important—a decided skepticism about the follies of human beings bearing governmental authority and power, reservations that demands instead of governments by people, a primacy of the rule of law. These principles work together in pairs or all together to guide Liberals as they attempt to participate in democratic self-governance. These principles are the axioms from which the logic of Liberalism is constantly evolving.
It is the job of campaigning politicians to understand the principles and logic of an ideology, the tensions among the founding principle, but it is the job of the elected politician to understand the lay of the land, the competition among programs and policies and the likelihood of assembling a sufficient number of votes to bring these programs and policies into law. Political parties help in this process by reducing the number of variables to that dozen or two that the average person is able to comprehend at a given moment. A political party that contains persons with inconsistent principles is sure to be ineffective, but equally a political party that rejects persons with new ideas is destined to die. This is the essential tension of "big tent" politics, that balancing act that discriminates the conflict of ideological premises from the conflict of competing programs and policies. Ideological premises have to be consistent, if not exactly congruent. Programs and policies, on the other hand, can be sorted out, the ones inconsistent with political logic rejected and the rest put into a political queue for eventual law making.
I have argued and continue to maintain that American Conservatism and American Liberalism are fundamentally inconsistent at the level of premises and logic. Conservatism is based on fear, a fear of the consequences of trusting men and women in office, because power corrupts. Accordingly Conservatives believe that the best way to avoid abusive government is to keep it weak and dispersed. Liberals on the other hand believe that while power often corrupts, it is still possible to keep men and women from misusing power by establishing and following rules of behavior, ethical standards, and both the letter and spirit of well-fashioned Law. Accordingly, Conservatism is a very poor platform for the development of progressive or humane programs and even worse for administering them ... as Nixon, Ford, Reagan and the Bushes have proven. The logic is wrong, whereas the logic of Liberalism actually promotes attempts to deal with issues that are otherwise intractible.
The natural allies of Liberalism would seem to be any group which also builds on Liberal ideological principles. Credential checking of Socialists, on the other hand, would reveal that their notions about government do not contain the strong skepticism about people in power, and they maintain an ideological commitment to the idea that private property is the is root of social and economic problems. This idea comes into immediate and usually fatal conflict with the Liberal principle of Individual Liberty. So, while Socialists and Liberals can co-exist in a nation, they are unlikely to be able to coexist in the same political party. Likewise, Libertarians believe that "market forces" are the something that people skeptical about authority can trust. The logic of market forces demands a belief that supply, demand, and competition somehow eventually produce progress and humane treatment of our fellow man. There is a possible argument for market forces producing some kinds of progress, but not every new product or service is progress, nor do the battles between producers result in invention and material improvements. Libertarianism is unquestionably mute on and ignorant of compassion. For this reason Libertarianism is logically inconsistent with Liberalism.
As the election of 2008 draws closer and closer we will see jostling within both the major "big tent" political parties for position and expression of ideological principles that individuals believe support the array of programs and policies they desire. We will also see the proponents of ideas with inconsistent logic edged off the stage until they can express their goals in a manner that is consistent with the premises of the majority.