Land commissioner's nod gives the New Yorker 11 of Arkansas' 12 superdelegates.
Rare superdel pick-up for Clinton since Super Tuesday.
Earlier: Montana Obama superdelegate retracts endorsement, saying state party rules block her from taking sides in a contested primary.
Plus: Second Montana superdelegate plans to support Obama, but may reconsider if Clinton wins popular vote.
And: Montana Governor Schweitzer plans to throw his superdelegate support to the winner of the state's June 3 primary.
