The Only Possible Explanation

How to get a handle on the irrationality of the left?

They aren't bound by the laws of logic or cause and effect like the rest of us.  They're driven by their fantasies, and they appear willing to abandon a system that's worked for hundreds of years to the benefit of people all over the world, and replace it with something that has been an abysmal failure every time it's been tried.  And they believe they can do this simply by wishing it into existence.

Here's just a couple of the kinds of things they are prone to say in pursuit of this fantasy:

Kathleen Sebelius:  "There is absolutely no evidence, and every economist will tell you this, that there is any job loss related to the ACA." 

Barack Obama:  "There is not a smidgen of  corruption in the IRS targeting of conservative groups".

Nancy Pelosi:  "Not having a job is a good thing, because it allows you to learn the piano".  (So I guess we don't need to worry about things like how you're going to feed your family.  The state will take care of everything).

There is only one possible explanation for this kind of strangeness:  leftists are all from a different planet.  According to theoretical physicists, there exist an infinite number of interwoven parallel worlds.  These planets may appear identical on the surface, but can differ in surprising ways.
  
The world conservatives inhabit just happens to have three dimensions which we conveniently call X, Y and Z.  Anything in 3D space can be located precisely in terms of those 3.  This gives rise to a predictable, logical world where cause and effect can be predicted and measured.  This works in the physical world, and it also works in such things as economics, and the dynamics of such things as health care systems.   Conservatives function just fine in a world such as that.  Earth is such a place.

Other worlds may appear identical at first glance, but may in fact have many more dimensions.  Possibly the number of dimensions on one of these planets can be changed from time to time by the issuance of an Executive Order.  In such a world, things like logic, cause and effect, and rational consequences of actions may not exist, and denizens of such a world may not have the ability to grasp such concepts. 

So that's it then.  Progressives come from this other planet, let's call it Unicornia, (you may have a better name, if so stick it in the comments) which may have, who knows, 11 dimensions or something, and you just can't expect them to have a clue how things work on Earth.

Here's a conceptual graphic of an infinite progression of worlds.  For the sake of clarity, Earth is the one in front, and the others may appear identical, but all have different spatial geometries.  See if you can spot the planet where all the liberals came from: