Political Status of Puerto Rico: Background, Options, and Issues in the 109th Congress [May 25, 2005] [open pdf - 194KB]
From the Summary: "Puerto Rico remains subject to congressional jurisdiction under the Territorial Clause of the U.S. Constitution. Under this authority, Congress has passed legislation that governs elements of Puerto Rico's relationship to the United States. For example, residents of Puerto Rico hold U.S. citizenship, serve in the military, are represented in the House of Representatives by a Resident Commissioner elected to a four-year term who does not have privileges to vote on the floor of the House, are subject to federal laws and are beneficiaries of federal aid as approved by Congress, do not vote in national elections, and pay no federal income tax."
CRS Report for Congress, RL32933