I'm no sports fan, but it's pretty clear that countries with more people win more Olympic medals. The obvious explanation is that people typically play for the country they were born into, and the ten best basketball players in China are likely to be far better than the ten best basketball players in Luxembourg.
Now suppose we take a cynical view of intellectual debate, and posit that it's basically like athletics. People typically argue for the view they were born into. Almost all Christian writers were raised Christian, and almost all Muslim writers were raised Muslim. So what happens if you have a big debate, where each viewpoint sends forth its ten smartest and most articulate thinkers to be its Intellectual Gladiators?
The expectation is that the advocates of the most popular viewpoints will prevail. The smartest ten Christians are going to be way smarter and way slicker than the ten smartest Zoroastrians, and will run circles around them in a debate.
Now here's the interesting thing. If virtually everyone just argues for whatever position he was born into, a truth-seeker should hold the gladiators for popular views to higher standards. If the smartest Zoroastrian holds his own against the smartest Christian, the rational inference to make is: "The Zoroastrian position is more likely to be true, because it tied despite the fact that it probably had a weaker defender."
Of course, there are a lot of factors that can mask or augment this effect. The adherents of one view could be smarter, or more intellectually aggressive, or be the gate-keepers of the Intellectual Coliseum. And in a debate all these things rationally count against the truth of the advantaged position!
This assumes, of course, that people always defend the views they were born into. If smart people are unusually likely to convert to the true position, then all else equal, smarter adherents should inspire confidence, rather than mistrust. (Libertarians and atheists, feel free to pat yourselves on the back.)
Who cares? Well, as an academic, it's hard not to notice that liberals dominate at the university. And the simple truth is that people at top schools are smarter than people at lower-ranked schools. The result is that in any intellectual debate, the best liberals are usually smarter than the best non-liberals.
If my analysis is right, however, this actually counts against the liberal view. Weren't most professors liberals long before they had any arguments for their position? And wouldn't it take overwhelming intellectual firepower to drive them to apostacy? Then it's no wonder that the smartest liberal academics are smarter than the smartest non-liberal adademics. They have the same kind of inherent competitive advantage that China has over Luxembourg.
The upshot is that if an academic debate seems tied, the non-liberal view is more likely to be right. And if the liberal view actually seem to be losing, it's a safe bet that it's wrong.