earlier blog post on the schedule to see when and where each level will be played and I've added links to the PDFs the USTA published.
The first question is, why are there wildcards?
For the women, there are 14 sections represented, and this doesn't work well with two flights (7 teams) or three or four flights (different numbers of teams in each flight), so you can see that a wildcard gets you to 15 teams which nicely fits into three flights.
For the men though, there are just 12 sections represented which would have made for a nice three flights of four teams each, but instead there is one wildcard and 13 teams with one flight having give teams. My only guess is that the USTA thought two more sections would send teams like was done for the women, and so would have five teams in each flight and needed the wildcard, but then two teams elected not to go but the wildcard had already been invited so couldn't very well rescind the invite.
If that is the case, I'm not sure why the second place team from those other sections didn't go, or why they didn't extend more wildcard invites, but perhaps they did and there just wasn't time for other teams to make the plans. If anyone knows the real reason, feel free to comment here or on Facebook.
But then the question becomes, from what section should the wildcard(s) come from? And why did Southern get both the men's and women's? Is the USTA showing favoritism to Southern?
Again, guessing here, but I think I have the likely answer. In my section (Pacific Northwest), we used to have a rotating wildcard from the different districts for Sectionals when there was a need for a team or two to fill out the flights. This changed a few years ago so that the wildcard simply go, in order, to the districts that fielded the most teams at a given level. In the PNW's case, this usually means Seattle and Portland get the first two wildcards as those districts have more teams than Southwest Washington, Southern Oregon, Eastern Washington, etc.
So, if the same logic is used for wildcards at Nationals, I believe that Southern, being the largest section with a whopping nine states represented, likely has the most teams at the 18+ 5.0+ level and so they are granted the wildcards.
If anyone knows for sure or has another theory, please comment. But perhaps the USTA isn't showing favoritism to Southern after all, and they are simply applying what would be pretty logical rules.