"In historical and constitutional terms, the recent political status vote in Puerto Rico was a necessary but obviously not decisive step on the road of self-determination leading to full self-government"

This quote by Dick Thornburgh speaks with the recent political status vote in Puerto Rico. He acknowledges that the vote was needed, but not definitive, in terms of Puerto Rico's journey towards complete self-government. This implies that the vote was a step in the right direction, but that there is still more work to be done. Thornburgh is likely referring to the fact that the vote was non-binding, which the US Congress will ultimately decide the fate of Puerto Rico's political status. He is also likely describing the reality that the vote was split between 3 alternatives, none of which received a majority of the votes. This implies that individuals of Puerto Rico have yet to reach a consensus on the issue. Eventually, Thornburgh is highlighting the significance of the vote, while also acknowledging that it is just one step in the procedure of Puerto Rico's self-determination.