As conservatism enters a new era, and a new challenge, during the Trump presidency, it's useful to clarify the difference between liberalism and conservativism. There are different ways to draw the line. Here's one way.
Liberals, secular humanists, and/or secular progressives assume that every human problem has a human solution. For some, that's an explicit article of faith. Others may not have that articulated belief, but they operate as if that's the case. Let's call this the myth of human perfectibility.
So, if every human problem has a solution, what's the source of the problem and what's the solution? Answers vary. Some liberals think social ills are due to the inequitable distribution of goods and services. That requires the state to step in to redistribute goods and services.
Some liberals think social ills are due to defective social conditioning. On this view, human nature is a blank slate. That requires the state to step in through compulsory public education, with a centralized curriculum, to indoctrinate students in socially enlightened values. Likewise, the state must step in to legislate speech codes. And so on.
Some liberals are more pessimistic insofar as they think social ills have a hardwired source: a throwback to our animal ancestry. We evolved from predators who had to fight to survive on the African savannas. Men are especially bad.
However, transhumanists are more optimistic. Perhaps we can rewire the brain through genetic engineering and bioengineering (e.g. neural implants, cyberware) to eliminate antisocial traits that produce social ills. Once again, this requires the state to step in, a la Brave New World.
By contrast, conservatives don't assume that every human problem has a human solution. Indeed, they generally regard some human problems as humanly insoluble. Secular conservatives base this in part on human history. Given man's evident penchant for violence and criminality, social ills are inevitable. Secular conservatives might also augment that by their belief, shared by some liberals, that this is in our genes. An inheritance from our nasty animal ancestors. The "killer ape". For their part, Christian conservatives attribute social ills to original sin.
To say social ills are inevitable doesn't mean nothing can be done to improve the situation. We need enough government to keep crime from spiraling out of control. But because social ills can't be eliminated, the role of government is limited, since government has limited ability to control crime. Moreover, some social ills are best addressed within the private sphere (e.g. church, family).
So a primary role of gov't is to keep crime at manageable levels. When gov't aims at something more utopian, gov't becomes dangerous. That's in part because bureaucrats aren't morally superior to the general public. If there's no check on the power of gov't, then who polices the police?
In addition, when the state is too powerful, it becomes a magnet for the criminal class. That's where the action is. That's the greatest racket in town. Totalitarian regimes are notoriously corrupt and crime-ridden.
From a conservative perspective, the state is on a knife-edge. Too little gov't, and you have rampant crime. Too much gov't and the state becomes arbitrary, unjust, suffocating, or a criminal syndicate in its own right.