My correspondent writes:
One thought with respect to partisan polarization. It does have something to do with team work. Our Members see themselves as much more part of a team now than ever before (team work on fundraising, voting, and agenda-setting are all in high gear) We operate more like "shirts and skins" than I ever remember. Here's a related point. I think the rise of more organized interest group behavior has something to do with it too.
Most lobbyists are shirts and skins now too. It wasn't always this way. Lobbyists used to play both sides of the aisle. Some still do, but the "rise of the partisan lobbyist" is something that needs to get built in to the polarization story.
Further, most interest groups (or lobbyists) don't stake out positions that are focused on enacting a legislative product. They are focused on reflecting their own best interests and ideal positions, often wrapped in a communications narrative that fits the particular party they are trying to win over.
To the extent that lawmakers support these positions (to win financial support, get good scorecard ratings, etc) they are supporting positions that move away from consensus rather than toward it. Interest groups are strategic, just like Members. And I think this leads their lobbyists to take positions that make finding consensus with the Senate and the President more difficult.
Changes in technology and the tools interest groups now use have made it almost impossible for lawmakers to support compromises without getting savaged from groups that are not getting everything they want from the policy process. Bottom line: interest groups (and the rise of the institutionalization of lobbying) may have a role encouraging Members to act more like teammates and encourage more polarization.I thank my correspondent for his willingness to share and promise to revise and extend as needed.