Michael Gerson has a pretty interesting column noticing that the Democratic Party is riven in two, while the Republican Party is unified:
Republican leaders have proved themselves capable of producing proposals that unite perhaps 90 percent of their congressional delegation, losing just a thin margin at each end of their ideological spectrum. But the job is made easier by the narrowness of the Republican ideological spectrum. A party that used to range from moderates to Reagan conservatives now ranges from Reagan conservatives to Tea Party conservatives, both offended by President Obama’s fiscal excesses.
On fiscal issues, the Democratic Party is really two parties. One consists of European-style social democrats, represented by leaders such as Nancy Pelosi. ...
The other Democratic Party is socially liberal and pro-business. These Democrats attempted to weed out the excesses of Obama’s health reform in the Senate.
Gerson doesn't attempt to explain the cause of this asymmetry, which has long interested me. My argument is that it reflects two interrelated things. Economically, the GOP has a relatively unified base: business. Of course, businesses can disagree with each other, but the business perspective is relatively unified on economic questions. The Democrats, by contrast, have an economic base holding together business as well as labor and environmentalists. It's a highly fractured coalition.
The ideological asymmetry, which in many ways stems from the underlying economic asymmetry, is that the Republican Party is the political arm of the conservative movement, whereas the progressive movement -- to the extent one even exists -- is merely one actor jockeying for influence within the Democratic Party. The Republican Party has a coherent economic philosophy -- government intervention bad -- whereas the Democratic Party is primarily a catchbasin for those who disagree with the Republican philosophy. (One result of this asymmetry is that, as Jacob Weisberg notes, the GOP is uniquely prone of constructing an alternate reality impervious to expertise and data.)
Naturally, Gerson imbues his argument with a pro-Republican spin. The GOP is the party of fiscal seriousness, he argues, belying the entire history of the last three decades, and especially the history of the presidency he worked for. Gerson argues that most Democrats are European-style social Democrats, citing as his evidence the fact "that they would have preferred a single-payer health-care system." It's a telling example. By Gerson's definition, nearly everybody in every advanced country except the United States is a socialist. Canadian conservatives favor single-payer health insurance. British conservatives favor state-run health insurance. Health care is just so inherently filled with market failure that it's possible to favor heavy government intervention there without having a general disposition to "increase the size and role of government," as Gerson writes. Indeed, it's impossible to oppose a heavily government-directed system of health insurance unless you share the theological fealty to free market superiority that is the unique province of the American right.
The people who lead the Democratic Party need to be able to craft policies that appeal across a fairly wide economic spectrum, and are usually mashed together under some forgettable slogan attempting to communicate the basic idea that markets usually work but we should correct them when they don't. The people who lead the Republican Party need to appeal to a coalition of business leaders generally interested in lower taxes and regulation, and they compete to embody a governing philosophy that takes a straightforward position that small government is good. The structure of the Democratic Party isn't always going to get things right, but the structure of the Republican Party is almost guaranteed to wind up advocating policies heavily tilted toward the interests of a narrow economic elite.