Most vulnerable Southern state for Republicans

[TJ in Oregon]

Oh it is definitely affecting the south, including Atlanta and Houston already. The Dallas and Phoenix metro areas are still soo staunchly Republican they aren't about to change any time soon. Both have diverse, liberal enclaves, but they're only a tiny fraction of the population. You also don't notice it as much in the south as a lot of places because the states aren't swing states for the most part (except VA, NC as noted).

One other note on your post, the area of the county least affected by the rise of the liberal gentry is the Great Lakes states. Most of the rust belt has bleeding people forever and hasn't attracted the types of upscale voters that have turned VA atlas red. This is one of the reasons why some of political predictor types like to anticipate the Great Lakes States trending toward the Republicans. That reasoning is true at the moment, but only because of the definition of "trending", ie. the rest of the country is rapidly moving toward the Democrats but the Great Lakes States haven't moved any direction at all, so compared to the average have trended Republican.

[TJ in Oregon]

Cleveland is still the Democratic stronghold of Ohio and will almost certainly remain so for a long time, but it's not because of an influx of liberal gentry, it's heavily Democratic because it has a very large blue collar industrial population and a large black population. It's a union vote Democratic area. It's slowly shrinking in population and the west side will probably have a Pittsburgh-like phenomenon in 30 years or so, but it has more liberal eastern suburbs and a larger black population than Pittsburgh so I can't see it trending quite as hard.

Cleveland's history is that of immigrant waves coming and settling in little ethnic neighborhoods built around a church or two nearby a factory. During the 60s and 70s, the combination of shuttered industry and racial tensions started the suburbanization process and caused people to begin fleeing the metro area. It was managed much better than Detroit and the city itself actually has a budget surplus and can function as a government, but much of the city is still a shadow of its former self. The Republicans have made inroads in the white ethnic groups, mainly because of social conservatism (ie. abortion, gay marriage, etc) but will have a very hard time actually winning there because of free trade and union issues. As a result, a lot of the more working class areas vote more lopsidedly in favor of the Democrats on the local level than the presidential level.

Also I used to live in Cleveland

[TJ in Oregon]

One interesting case though is that of Minneapolis. Though MN is that famous state which voted twice against Reagan, it seems to be trending Republican, or at least staying stable, over those last years. And differently from the Rust Belt states, MN is actually thriving.

I'm generally of the opinion that Minnesota would be one of the very last Midwestern non-Illinois states for the Republicans to win. It and Ohio were the only two Midwestern states to trend toward Obama in 2012. Minnesota does have a staunchly conservative exurban base and German Catholic base, the Republican party doesn't seem to be making any inroads into the Democratic strongholds up north or in the Twin Cities.

The MN state GOP is a also total mess. Perhaps being a Republican living in Wisconsin I'm a bit biased, but I have a hard time watching the state Republican Parties in Wisconsin and Minnesota and seeing them win Minnesota and not Wisconsin. The Wisconsin GOP is able to win on off years somewhat consistently and has people viewed as national caliber figures from Wisconsin such as Reince Preibus, Scott Walker, and Paul Ryan, who can actually get people to vote for them, while Minnesota has, err, Michelle Bachmann. I agree there's some potential still in Minnesota and that there's a Republican base as well in Minnesota that will make the elections look somewhat close, but it's hard to see the Republicans getting over the hump in Minnesota.

I think our better opportunities are PA, IA, and WI.

[TJ in Oregon]

Cleveland is still the Democratic stronghold of Ohio and will almost certainly remain so for a long time, but it's not because of an influx of liberal gentry, it's heavily Democratic because it has a very large blue collar industrial population and a large black population. It's a union vote Democratic area. It's slowly shrinking in population and the west side will probably have a Pittsburgh-like phenomenon in 30 years or so, but it has more liberal eastern suburbs and a larger black population than Pittsburgh so I can't see it trending quite as hard.

Cleveland's history is that of immigrant waves coming and settling in little ethnic neighborhoods built around a church or two nearby a factory. During the 60s and 70s, the combination of shuttered industry and racial tensions started the suburbanization process and caused people to begin fleeing the metro area. It was managed much better than Detroit and the city itself actually has a budget surplus and can function as a government, but much of the city is still a shadow of its former self. The Republicans have made inroads in the white ethnic groups, mainly because of social conservatism (ie. abortion, gay marriage, etc) but will have a very hard time actually winning there because of free trade and union issues. As a result, a lot of the more working class areas vote more lopsidedly in favor of the Democrats on the local level than the presidential level.

Also I used to live in Cleveland

Its a shame what happened to the so-called "Rust Belt". Those cities have by far the coolest skylines, and are in my opinion the most beautiful cities in America. I like "old" cities. Unfortunately, even with 5 decades of decline brought by unionism, they still seem not to learn. Whilst Whites down South have long shifted to the GOP, many ethnic Whites up there seem to be very stubborn going Republican. I'd say even the old southern Whites were not that stubborn leaving the Dems.

Think about it from the perspective of the workers. Many of them were employed on a line somewhere in a manufacturing plant doing the same job every day for years and years and thanks to the union, were able to live a reasonably comfortable 1950s style middle class lifestyle to raise their children. Then from 1960-1990, globalization slowly became a reality in a ton of industries, and they suddenly had to be able to compete with poorer countries around the world. Plants shuttered, industries collapsed, cities fell apart, and many of the workers hadn't accrued the necessary skills in their old assembly line jobs to compete in the information age. The unions, for all their ills, at least represented the worker's interests in some capacity, while no one else in the system did whatsoever. The unions were part of the problem in many ways, as they often bargained for unsustainable pensions and often took layoffs rather than paycuts (it's arguable depending on the circumstance which would be a better choice). But the mentality here of the unions as the enemy is a huge part of the reason why the white ethnic rust belt Democrats haven't become Republicans. Most people know the unions are flawed in many ways, but to so many workers, the unions, whatever they are, aren't the enemy. There are a lot of pro-life retired autoworkers in northern Ohio who vote straight-ticket Democrat every time. Why? Abortion doesn't affect them personally, the chances of their pension getting sliced does.

Now, the Democrats haven't shown lately any particular tendency to care much about the demographic I'm outlining here either. Eventually that will come back to bite them, and eventually the old union manufacturing types will die out. The question then becomes where their children end up adopting their parents' religious/moral beliefs or their partisan identification. It's not really a dichotomy either, people fall along a spectrum in between. It isn't a matter of making a play for them or not, like this forum often tends to think. The unions aren't nearly as important as they once were, which almost certainly benefits the Republicans. But the voter demographic I've been discussion here still isn't going to suddenly view the Republicans as acting on their behalf either. If anything, they'd be very unenthusiastic Republican voters.