Congressional Seats

We are told, over and over, that many Democratic Congress people are "risking their seats."  Risking what - "their" seats?  Whose seats are these?  It is a scandal that many people in Congress base many of their actions on the potential impact on their reelection chances.  It is a well-known scandal - why is it not a focal point of news, a big issue?  These are the people's seats.  It is a travesty of the idea of "public service" that we all know that people in public office are MOST concerned about keeping their jobs, not about fulfilling roles defined by our democratic system.  It is not good enough that public communication about this issue is confined to mild lamentations, followed by moving on with "the news."  THIS is the news - our government is poisoned by the lack of interest in our officials to actually perform PUBLIC service.