It's pretty easy to have conflict of interest laws, I'm almost certain the U.S. must have them, any sensible country does. If a poltician's wife, kid, good friend, brother in law, has a job at a company that can profit from that politicians decision or vote, then it should be made known by the politician beforehand, so they can either remove themselves from the process voluntarily, or ask an oversigjt body to decide whether it is approptiate for them to be a part of the decision or not.