Earlier this week, we wrote about how demographic shifts in the South could help Democrats become more competitive in a region that has swung significantly toward Republicans in recent decades. Some folks took issue with that analysis. Below is a counterpoint from Rob Richie and Devin McCarthy of FairVote, a group that advocates for changes to the U.S. electoral system.

The great hope of many Democrats is that Republican strongholds in the South will soon become purple or even blue as a result of inexorable demographic trends. Tuesday in “The Fix,” Chris Cillizza reinforced that hope, arguing that the South will become a “genuinely competitive region over the next two decades.”

While the demographic trend of a growing Hispanic population in the South is real, its effects are overstated. Yes, a few Southern states are getting more Democratic – but at a glacial pace. Meanwhile, Southern Democrats have experienced a massive loss of power over the past two decades as white voters became overwhelmingly Republican: Democrats have gone from holding two-thirds of Southern House seats in 1990 to less than one-third today, and from having majorities in 28 Southern state legislative chambers to only three today. (For the purposes of this analysis, the South doesn't include Delaware, Maryland and Washington, D.C., which have long been Democratic.)

One reason that Cillizza's conclusions overreach is that he compares the 1988 presidential election, in which George H. W. Bush trounced Michael Dukakis by eight percentage points, with the 2012 presidential election, in which Barack Obama defeated Mitt Romney by four percentage points. Bush performed about seven points better in South Carolina in ’88 than Romney did in ’12, but he also outperformed Romney by six points nationwide.

Using FairVote’s partisanship metric (which compares presidential vote shares in states and districts to their nationwide totals), South Carolina was 42 percent Democratic in 1988; in 2012, it was 43 percent Democratic. Georgia was 44 percent Democratic in 1988; in 2012, it was 45 percent. Even Arizona, the state likely to see the largest effect from a rising Hispanic population, moved only 1 percent toward Democrats from 1988 to 2012, from 43 percent to 44 percent Democratic.

While three of the 10 swing states in 2012 were from the South, this is hardly indicative of a regional trend toward competitiveness. Florida has been a swing state since 1996 and Virginia since 2004. North Carolina grew competitive more recently, but long has been on the threshold; it was already a 46 percent Democratic state in 1988, and Democrats won five straight governor’s races from 1992 to 2008.

Could more Southern states become real swing states in the next 20 years? It’s plausible, if Latinos continue to vote for Democrats at the rate they voted for Obama and if Latino turnout increases, as it has in more rapidly Democratic-trending states like New Mexico, Colorado and Nevada. But that would represent a break from partisanship trends in the South over the last 25 years -- not a continuation.

For congressional elections, southern Democrats’ plight appears even more hopeless. Because of the way districts are drawn and populations are concentrated, Democrats won just 28 percent of Southern House seats in 2012 despite receiving over 40 percent of the vote in those states. And these districts are not just a few percentage points away from becoming competitive due to demographic trends. Republicans hold a partisanship edge of at least 14 percent in 47 of 60 districts in the Deep South belt of the Carolinas, Georgia, Tennessee, Alabama, Mississippi and Louisiana. Barring national electoral reforms at the congressional level (such as FairVote's recommendation of fair representation voting), there is no reason to think this situation will change after the next census in 2020.

If Democrats are counting on voters in South Carolina, Georgia, Mississippi and Texas to win them the White House and Congress in 2024, they might want to come up with a backup plan.