The left are anti-market
The right are anti-foreigner
And once the primaries are over
They sprint to the center
Where the left try to prove just how anti-foreigner they can be
And the right try to prove just how anti-market they can be
And for the definition of Left and Right in broader terms, see Slatestar's Thrive/Survive theory of the political spectrum, or Bryan's simple theory of left and right.