I doubt that there are a million men in jail for failure to pay child support.
I read a couple of years ago it was @ 250,000 for back support.
Here's more information from Tennessee, but his involves felons:
"Felons with unpaid child support can't vote"
http://www.knoxnews.com/kns/state/article/0,1406,KNS_348_5036789,00.html
I also was hitherto unaware that failure to support your kids is a "conservative" value.