If control of the House and/or Senate flips to Republicans narrowly, it will be because of lost seats and lost opportunities in Ohio.
Five of Ohio's ten Democratic Representatives are in serious jeopardy, matched only in the more populous states of Pennsylvania and New York. Together, these three states account for 16 of the 51 Democratic seats ranked by RealClearPolitics as being Likely or Leaning Republican, or Toss-ups. (And Ohio has the only "Likely GOP" seat of the three -- OH-01). In addition one of the only Republican seats that had a high likelihood of flipping Democratic -- Jean Schmidt's seat in OH-02 -- was pissed away by open collusion with Schmidt by "leaders" of the Ohio Democratic Party in the primary.
On the Senate side, Kos had ranked the open seat now held by retiring George Voinovich as "the most likely Democratic pick-up." This would have been true, hypothetically, if the very same ODP "leadership" had not taken extreme measures to ditch, defame, and derail the one Democrat who could have beaten rising GOP star Rob Portman -- that was, of course, Jennifer Brunner.