In this year's presidential election, the American people will make a fateful choice: whether they want a liberal or conservative administration. Perhaps they will finally make up their minds instead of lurching from one political philosophy to the other as they tend to do.

But it is also possible Americans will choose a president in the traditional manner: on the basis of which candidate has the better hair, nicer-looking kids and the cuter dog -- important considerations, certainly, but ones that do not answer the pressing philosophical question.

To encourage voters to put aside political personalities for once, I am devoting today's column and next week's to the competing political world views of liberalism and conservatism and their contrasting strengths and weaknesses.

The problem with talking about left and right, liberal and conservative, is that the terms themselves have become mush. Illiberal liberals and un-conservative conservatives abound.

As for those "left" and "right" tags, they owe their lineage (and I kid you not) to the seating arrangements of delegates in the national assembly convened in late 18th-century France. Those who wanted a tax on snails sat to the left, those who said "non" to an escargot levy sat on the right (admittedly, a little kidding there).

The best I can do is to use these political terms as they are commonly used today. As a proudly self-identifying liberal, I will pick on the liberals first, because the meek shall inherit the Earth, and a good teasing will better prepare them.

According to my own definition, a liberal is someone who is tolerant of consenting adults having any sort of sex but does not approve of having a cigarette afterward.

This is true as far as it goes, but there are more issues than sex and tobacco, more's the pity. Liberals tend to dislike guns, corporations, discriminatory behavior (smokers excluded), inequality in its many forms, talk radio, union busting, Fox News, haters and mean people, which in their view is just another way of saying conservatives.

Notably missing from this list is any mention of the things that conservatives love to hate, including big government and taxes.

When it comes to government, liberals are descended from the goo-goos -- the good government guys of yore. They don't mind the government being big so much as they want it to be like a fond aunt: kindly and incorruptible and preferably cuddly. They would not be against a federal Department of Puppies and Kittens.

As for taxes, they want the rich to pay more of them, because the rich don't seem to be doing anything productive at the moment except having a good time, and that's so irritating.

If they don't get their way, liberals believe in nonviolent protests, such as creative sulking. They love a nice march, especially if it involves chanting and signing petitions.

But they don't really believe that the "tree of liberty must be refreshed from time to time with the blood of patriots and tyrants," as right-wingers do. Instead, they think a good organic compost will do the job.

But, you say, what about the anarchists, who have some rough customers in their ranks, and the occupiers with their in-your-face, in-your-park tactics? Good point -- and this is the difficulty of painting caricatures with a broad brush. I am a liberal, but I don't really think those on the far left are liberal, just as I don't think those on the far right are conservative. In my view, those on the extreme opposite poles of the political spectrum have something in common: They are both nuts.

But liberalism is also hard to define for the great mass of its adherents. There seems to be no common thread of belief other than having the government involved in taking reasonable actions for the common good. This sort of liberalism seems less a universal belief system than a collection of random acts of idealism.

To test this theory of mine, I asked if anyone on my now-defunct blog could come up with a definition of liberalism in 25 words or less. Nobody quite managed it.

And that's the central political problem for liberalism's brand. Liberals are generally kind, good, smart people who make excellent lovers, simply because folks who hug trees really warm up when they hug people (kindly remember not to smoke).

But liberals struggle to define themselves, unlike conservatives who are very clear about what they stand for, making them far more politically effective, as you shall see next week when I pose the question: Conservatives -- are they bad to the bone or merely out of their minds?

Reg Henry is a Pittsburgh Post-Gazette columnist. Email