This list of U.S. Senators with their mail message addresses is very helpful if you want to get a message through. On a recent Senate issue, I wrote the Senator who represents me. I'm sure the message I got back was canned, with so many people writing, but what I've been told in the past is that records are at least kept by Senate aids of the positions of people writing or calling. For me, this direct contact is a lot more meaningful than many (not all) petitions that circulate and, I suspect, often don't end up getting sent anywhere. Most don't even have instructions re where to send so they just disappear into the Internet.