Major- maybe the definition you have of NEastern Republican, ala Olympia Snowe etc., is a more traditional definition of a Republican, whereas the Republicans elsewhere, or at least those running under the GOP name are what have changed.
It wasn't long ago in my home state where Ann Richards was Governor, being a Democrat was not a dirty word, and Republicans and Democrats often worked together to resolve issues when something urgent arose. Sure, there have always been 'battles'- but nothing like today's fights where being re-elected supersedes resolving a problem for the country.
I believe there is a Republican party, which has various branches within it- some moderate, some Conservative, and a Tea Party faction who has shown that they will often not vote with their GOP leadership at any expense. Not voting along your own party surely demonstrates a separate branch within the GOP- and they've proven this multiple times already.
I believe Boehner is a moderate Republican struggling to keep various GOP factions together. We could say the same for the Democrats at various times when they owned the House- but right now they dont.