What's taking so long for Puerto Rico to become a state?

[Redalgo]

The impression I've got is that the three major parties in Puerto Rico define themselves in large part by their stance on this issue - whether to remain a commonwealth, seek independence, of have a go at statehood. The Independence Party has lost a lot of ground while the dominant Popular Democratic Party favours commonwealth status and is the local equivalent to the Dems up here. The second most prominent party, the conservative New Progressive Party, is the one interested in statehood and is most sympathetic of these three toward the GOP.