This quote from Senator John Thune, #2 in the Senate Republican leadership, pretty much distills into a sentence the thesis of my work on why the shared electoral fate of same-party members in the White House, Senate, and House — in an era of nationalized elections and hyperpolarized parties — means that the system of checks and balances no longer functions as the Framers envisioned:

“I just think that everybody realizes that our fortunes sort of rise or fall together,” said Sen. John Thune (R-S.D.), the party whip. “One thing we have to do is to make sure that we are united on our agenda and make sure that there’s not separation between the White House and Republicans in Congress.”