There will be a congressional vote today to determine whether or not to give Puerto Ricans a choice on the status of Puerto Rico with respect to the US. In the current system, the "status quo", Puerto Rico is a colony of the US. We receive certain benefits, such as Medicare, Medicaid, and food stamps (limited compared to what you get in the US). We don't pay federal taxes, but we do pay SS taxes and serve in the armed forces. Puerto Ricans have historically voted for retaining the status quo over the other two options: statehood and independence.
In last election, Fortuño was elected governor. He was the Republican candidate: here, that means pro-statehood.
So suppose you were pro-statehood, and you wanted to rig an election in your favor. Here's how, using a brilliant ice cream analogy of my own design.
Say the only three ice-cream flavors are chocolate, vanilla and strawberry. 49% of the people want chocolate, 47% want vanilla, and 4% want strawberry. You really want vanilla to win, so you break the vote into two parts:
1. Do you want chocolate? Surprise! The people say no!
2. Since you don't want chocolate, do you want vanilla, or do you want strawberry? Surprise, vanilla wins!
Democracy in action!