The Big 12 has announced that they the Missouri Tigers will be given until the end of the 2011-12 academic year to decide if they wish to leave the SEC and that the the Big 12 is set at 10 teams. This is not the best of news for Mountain West fans, because had Missouri left to join the SEC for the fall of 2012 the Big 12 would have reacted by adding Big East schools and possibly ending the Big East as a football conference and potentially allow the Mountain West to slide into the Big East's BCS spot.
With Missouri staying and the league most likely staying put at 10 teams means that Boise State who has been linked to the Big 12 is definitely not an option even though that was most likely the case when the Big 12 finalized a new six-year media deal that split revenue equally amongst all 10 teams. Also what is not to be lost in this is that Missouri did not have the necessary votes to be invited to the SEC.
The downside to this is that Missouri most likely will be making overtures again next summer and we will be filled with another expansion plagued summer of will they or won't they. Also, with the Big 12 not raiding the Big East it makes that league more stable and increases the chances that Air Force would jump ship and join the Big East without having to worry about the league falling apart.