The process relies upon thorough documentation in order to demonstrate the existence of the qualifying relationship and the fulfillment of all other requirements. Due to the complexity of the law, constantly changing regulations, and unwritten codes of procedure, there is a significant element of risk. A number of insensitive bureaucracies may be involved. There is a limit to the number of immigrant visas available each year for all but spouses, minor children and parents of US citizens. Delays may be imposed by quota restrictions.
Processing delays are also inherent in the system.
While the law is federal and so must be applied evenly throughout the nation, processing times and procedures vary from state to state and month to month. Permanent residents enjoy most of the same rights and responsibilities as US citizens, with the exception of the right to vote and to hold certain sensitive jobs or investments. Travel to and from the US is simplified, and no paperwork is necessary to maintain the status. Movement within the country and from job to job is unlimited. Permanent residents are taxed on their worldwide income.