Classical liberalism is not a static political philosophy. But it appears that some are trying to make it so.
The issue that brought this to mind was the debate regarding marriage equality. And, while that got me thinking about the issue, it is not directly relevant to the broader issue of the dynamic, or static, nature of liberalism.
One opponent of marriage equality argued that support for this right is not liberal becauseJohn Stuart Mill never said anything about gay marriage or civil unions.
True as his observation might be, his conclusion is not constructive to the debate nor particularly relevant. There are several things contained in his remarks. But at the core of it is the idea that liberalism is static.