But while I was looking through the polls to figure out where Perry is getting his support, I ran across a startling table that tells us a lot about the Republican Party, and why Perry has taken off so fast.

Check out this link and scroll down to page 5 of this CNN/ORC poll released this week. Note all the columns with “N/A” all the way down — every region in the country except the South.

What this reveals is that the only region in which there were actually enough Republicans to analyze was the South. In every other region, the pollsters just didn’t run across enough GOP loyalists to offer a responsible analysis. (And kudos to CNN/ORC for being statistically responsible here.)

Now check out another chart on the next page, by age. Here, again, the Republican shortage is striking, this time among younger voters. The only groups that provided enough Republicans to analyze were in the two categories 50 and older.

Yes, the GOP these days is pretty old and pretty Southern. It’s also very conservative. Any wonder why Perry has taken off?

Now, a few important caveats: The CNN/ORC Republican sample is pretty small nationwide, just 467 people. So it’s not surprising that when you spread those folks across regional and age groups, there are some very low numbers in certain categories. Other surveys (Gallup for example) found enough Republicans to analyze in these missing categories. The Pew Research Center in July also found that the GOP has made gains among young whites since 2008. And, Lord knows, none of this means that Republicans can’t win with the demographics they have — they did do rather well in 2010, as I recall.

But there is still a decided Republican weakness among the young, which means that to win, Obama needs to work hard to turn out these voters in 2012. He could also lose states in the Deep South by a landslide and still win the election elsewhere. The GOP’s age and region problem will haunt it in a high turnout election. We just don’t know yet if that’s what 2012 will be.

As for the GOP primary campaign, Gallup’s numbers are instructive: Perry’s lead is primarily a Southern phenomenon. According to Gallup, Perry leads Romney 39 percent to 12 percent (with Ron Paul at 9 percent and Michele Bachmann at 8 percent) in the South. All the other regions are close. In the Midwest, Perry is ahead by only 23 percent to 20 percent for Romney (with Paul getting a healthy 18 percent and Bachmann at 15). In the West, it’s Perry 28, Romney 22 and Paul and Bachmann at 12 each. And in the East, it’s Romney 17, Perry 16, Paul 15 and Bachmann 12. Put another way, Romney is in striking distance everywhere in the country except the South.

Perry’s constituency is also older than average. Among Republicans 65 and over, it’s Perry 40, Romney 16, Bachmann 10 and Paul 4. But Republicans under 30 are a completely different (and far more libertarian) party. In this group, Paul leads with 29 percent to Perry’s 21 percent, Bachmann has 12 and Romney has 11.

In a party as relatively old and relatively Southern as the current GOP, you have to like Perry’s demographics. But there are primaries outside the South and — as of now, at least — that’s where Romney will have to succeed if he’s going to win this thing at all.