It is no accident that secularism and progressive politics go together. It's basically because the left has made a religion of politics by applying Christian principles and values, a disastrous move which inevitably leads to economic, political and social decline - as we see dramatically illustrated in the decline of Europe, and, increasingly, America as post-World War II social welfare policies and an out-of-control notion of human rights take their social and economic toll.
The irony is that the dangers of applying Christian principles in the political sphere have been known about and talked about by many thinkers, religious and unreligious, Christian and non-Christian, in the course of the last two thousand years.
I recently came across this reference to the views of Martin Luther (a thinker who once meant a lot to me).
Luther rejected philosophy - and so logic and reason - as a starting-point for faith. He drew a clear distinction between the law and the gospel, between conscience and faith.
"[U]nlike most of his contemporaries, Luther did not believe that a ruler had to be Christian, only reasonable. Here, opposite to his discussion of theology, it is revelation that is improper. Trying to govern using the gospel as one’s model would either corrupt the government or corrupt the gospel. The gospel’s fundamental message is forgiveness, government must maintain justice. To confuse the two here is just as troubling as confusing them when discussing theology. If forgiveness becomes the dominant model in government, people being sinful, chaos will increase."
Secular conservatism is a difficult path to follow because it doesn't provide an outlet for our religious instincts. It's 'unnatural' in fact, like science (both requiring an overthrow of built-in instincts and proclivities). I fear it is destined to remain a minority position.