I want to find out whether I'm doing something wrong, and where to look for similar thinking. Imagine a thin wire that carries a constant electric current. Negative charges move to the right. Positive charges are stationary. The charges balance on average, or maybe there are a few more negative charges to the left and fewer negative charges to the right. Apart from perhaps a small gradient, the distribution of positive charges and of negative chargeds are both uniform. Choose a positive charge at the center. What forces are on that charge? My first thought is to say that there are an equal number of stationary positive charges on both sides, so those cancel. And there are nearly equal negative charges on both sides, so those mostly cancel too. It takes time for the force from an electric charge to arrive at the center, so the forces we add up to get the total force at one time will actually reach back into the past. They are "retarded" forces. But that doesn't matter because it's a steady state and there were just as many charges in each location in the past as there are now. But wait, it does matter. Right now the electrons are uniformly distributed along the wire. At any time in the past the were uniformly distributed. But the ones we add up to get the force right now are not uniformly distributed. The farther we go back into the past to find charges that affect the center right now, the more those charges move before they reach their uniform distribution today. If the charges travel at speed v, then a charge that was at location -t at time -t will be at location -t+vt now. The charges that have a uniform distribution now were spread out across the various times that they created the force that affects the center now. Similarly, the charges on the right which are uniformly distributed now, were bunched together when they created the force that affects the center now. A charge that was at location t then, is at location t+vt now. So the charges on the left affect the center less than the charges on the right. When we sum, we sum over a path that's denser with electrons on the right than on the left. Charges that move away from each other should exert more force on each other, than forces that are getting closer. Have I left out something? Not magnetism. There is no magnetism unless both charges are moving. I think not relativity. Time dilation and space contraction are the same whether you are coming or going, right? All I can think of, is that maybe when a charge is approaching, its electric force is kind of squeezed in front of it. So the force is denser even though the charges themselves are less dense, and maybe that cancels out. Or possibly that hypothetical gradient creates the average velocity, and the charge effect due to velocity is exactly balanced out by the charge effect due to gradient? Where can I find the results the actual experts got when they figured this out?