MMA sanctioning is a strange and complex system, in that there isn't really a system. In the US, each SAC (state athletic commission) has the right to decide who fights and under what rules, they sanction fights and closely regulate the running of events, selecting the judges and referees for each bout. However because each state makes it's own decisions, things have the potential to get confusing and unsafe.
For instance, in Connecticut, West Virginia, New York and Vermont professional MMA is illegal, but surprisingly and perhaps worryingly so, (according the association of boxing commissions website) in Vermont amateur MMA is legal but completely unregulated, up until recently this was also the case in Alabama.
US and Canada
The "Unified" rules for MMA, those currently used by the UFC and widely accepted by commissions across the board, were originally published by the New Jersey AC in 2000. During the Association of boxing commission's (ABC) most recent conference in New Orleans, the rules were reviewed and accepted across the board. However there are still slight differences from state to state, for instance, double weigh ins in Massachusetts etc.The ABC is a coming together of commissioners of combative sports from across the US and Canada who work together to regulate fight sports, but there is no obligation for any state to adhere to, or even attend the conventions.
The ABC has moved things along greatly in terms of unifying rules in Canada and the US but has no legal power to enforce rule changes or regulations anywhere.
Japan and Europe
In Japan and Europe (shamefully enough for me, UK included), there is no regulating authority over MMA competitions. Such freedom can be seen as either an extremely good thing or an extremely dangerous thing. The fact is that any MMA promotion wants to be taken seriously, so dangerous rules being put in place just because they can be, is very unlikely and not something I've ever come across. MMA as we know it now has been around for about 20 years, and from what I can find, there have only ever been 3 reported deaths due to MMA related injuries, only one of which was related to a sanctioned bout in the US (Sam Vasquez). The other two happened in unsanctioned bouts in Ukraine and South Korea. There were also unconfirmed reports that Douglas Dedge, the fighter who died in Ukraine, had a pre existing condition that contributed to his death. So all in all, no matter where in the world you fight, sanctioned or otherwise, the chances of getting killed are extremely low, but there is no denying that properly trained and sanctioned referees and medical staff , make things far more safe. Another problem with the lack of regulation is that, without stringent testing for steroids and other growth hormones, substance abuse can be a problem. This has lead to fans and pundits often discrediting fighters achievements over seas. All in all if you want to fight MMA fairly and safely, then, generally speaking the US is the place to be.
A Licence to Fight
When it comes to who can actually get sanctioned to compete in MMA, it appears to be completely subjective. Depending on where in the States or Canada you apply, your fight may or may not be allowed to happen and fighters can be denied on all sorts of grounds. For instance Tim Sylvia was recently denied the opportunity to fight Wes Sims, on the grounds that the bout was deemed "non-competitive". What that means exactly, I'm not sure, but at the time, Sylvia claimed that the commission did not see Sims as fit to fight him. What we do know now however is that this match up is going to take place regardless in New Brunswick, Canada. The message seems to be, if you can't get what you want in one place, try the place next door, if you can't get it there, go somewhere without a commission. A lack of continuity between SAC's can cause problems, but the reality is, with MMA promotions all over Asia and Europe without the rules and regulations of the states, pretty much any fight can take place. Until the rest of the world catches up with the US, you will still find Jose Canseco fighting Hong Man Choi on any given night.
Thanks for reading