Not exactly. At first I thought some deep south states might still switch from D to R, but then I checked my hypothesis and found that the Deep South's switch from traditional Democratic representation to Republican was complete in 2004 when Zell Miller (D) retired and was replaced by a Republican in the Georgia senatorial election.
So why are the Republicans expected to take over the Senate in 2014, and why had it been expected in 2012? What are the developments that lead to that general expectation?
First, I'll dispel the notion that more states vote Republican than Democrat as a matter of course: Obama won 26 states in 2012.
So What Are The Trends?
To research this question, I used Wikipedia's list of senators, such as this entry for Maine. I looked at the patterns of the elections of senators. (Senators, being state-wide representatives, are better bellwethers.) I was surprised by the number of states that had mixed Dem/GOP electoral results for much of their history.
- Myth - the inland west was mostly Republican. They were all mixed until Idaho, Wyoming, Utah, and Arizona turned decidedly Republican.
- Myth - The northeast has been mostly Democratic for a long time. Northern New England was very Republican until recently. The northeast has turned mostly Dem only since the 1980s, while Northern New England remains mixed.
- Myth - The old Confederacy was solid Dem, and then became solid Republican. This isn't true of Virginia, North Carolina, Florida, Louisiana, and Arkansas.
- Myth - the rural plains and mountain states are strongly GOP. Surprisingly, North and South Dakota and Montana have a very mixed record, electing many senators from both parties.
- Myth - the west coast has been liberal for a long time. These states were also mixed until the 1990s when they started turning decidedly Dem.
The Dems don't have many states on which they can pin similar hope, at least for the 2014 election. Maine and New Hampshire have the potential to become more liberal/Dem. Until the demographics change in states like Georgia, Texas, and Arizona, Dems have to hope for lucky pickups or wins due to strong local candidates.
So the GOP will go into the 2014 senate elections favored to pick up seats.
Yes, Civil War Fallout
The biggest surprise is that this sunny outlook for the Republican is indeed Civil War fallout. Arkansas and Louisiana are both southern states that are coming late to the conversion from solid Democrat to solid Republican. But that is only part of the good news for the GOP. They are also benefiting from the shift of western conservatives to solid Republican status.
1959: A very different map. New York is red, Texas is blue.
The most solid Republican state is Kansas. No state has been solidly Democratic throughout its history.
Solid Democratic states: 12.
Solid Republican states: 15.
Northern New England was quite Republican until the 1950's, but the rest of New England has been much more mixed. Southern New England, mixed, then mostly Dem starting 2000
New York - mixed until late 1990's, then D.
New Jersey, no elected R since late 1970s.
Delaware - D until 1900, then mixed until 2000, then D.
Maryland - D until 1900, then mixed until 1980s, then D.
Penn - R mostly except during D waves.
WV - mixed.
Virginia - solid D post reconstruction until mixed starting 1960s.
NC - Mostly D post reconstruction until mixed starting 1970s.
SC - solid D post recontruction until all R after 2000.
Georgia - solid D post recon, mixed 1980's to 2000s, then all R.
Ala - solid D post recon until 1980's, solid R after 1990s.
Miss - solid D until 1980s, then solid R.
Kentucky - solid D post recon, mixed 1890s- 1990, then R.
Tennessee - almost solid D post recon, mixed 1970s, then R 1990s.
Florida - solid D post recon, then mixed starting 1960s.
Indiana - mixed.
Illinois - mostly R until 1930s, then mixed.
Michigan - solid R until 1930s, then mixed.
Wisc - mostly R until 1960s, then mixed.
Minn - mostly R until 1950s, then mixed/lean Dem.
Iowa - solid R until 1920s, then mixed.
Missouri - mixed, lots of reelections lost.
Arkansas - solid D until 1990's, then mixed.
Louisiana - solid D until 2000s, then mixed.
Texas - solid D until 1960s, solid R since 1990s.
Oklahoma - mixed until 1990s, then solid R.
Kansas - almost solid R throughout.
Nebraska - mostly R thoughout.
SD - solid R until 1910's, then mixed. Lots of lost reelections.
ND - mixed throughout.
Montana - mixed/lean D.
Idaho - mixed until 1960s, then R.
Wyoming - mixed until 1970s, then R.
Colorado - mixed since 1900s.
New Mexico - mixed.
Arizona - mixed until 1990s, then R.
Nevada - mixed throughout.
Utah - mixed until 1970s, then R.
California - mixed until 1990's, then D.
Oregon - mixed until now, now D?
Washington - mixed until 2000, then D.
Alaska - mostly R since 1980s.
Hawaii - solid D since 1970s.
Edit 3/23/14. Fixed mistakes. North Dakota isn't having a Senate election in 2014. Added W. Virginia and N. Carolina as likely to become more Republican. Also, 538 is currently predicting that the GOP takes control of the Senate. The GOP will probably try very hard to be more careful this year in their Senate nominations because of the mistakes in 2012. That will also increase their odds of taking the Senate.