It’s been nearly three months since he last cast a vote on the House floor, but Rep. Thomas H. Kean Jr. has been keeping busy — or at least trying to look like he is. In the New Jersey Republican’s absence, five speeches under his name have appeared in the Congressional Record. Staff in congressional offices continue to work even when their bosses don’t, which is nothing new. But Kean’s disappearance has raised long-overdue questions about transparency on the Hill, some experts say. “The appearance of impropriety is just as bad as the real thing because it casts a cloud...