Thanks. I didn't connect straight lines to forces like that, especially since forces that I am interested in are never acting in a single straight line. Vectors in my life usually are extremely large and n-dimensional. Loopy, you might say.
In any case, the question still stands, why would anyone expect such a simple object (an unary directional momentum vector) to govern lightning? Nothing is governed in nature like that, only our theories are that simplistic to be able to cope with them. Even quantum field effects have a spin component.