As a constitutional libertarian, if I were to run for president of the United States, Here's what I would propose how to deal with immigration and citizenship.
First, I would submit an end to the concept of citizenship. The founding documents quite specifically set forth that this is a country established to protect and be a steward of natural rights including life, liberty and the pursuit of happiness among others for everyone living here.
If someone declares residence here, and signs an affidavit signifying their acceptance of and agreement to abide by the founding documents of the U.S. and the state they live in, they are "covered" for as long as they reside here. When and if they move into another state within the U.S., they must agree to abide by that new states constitution. All residents in any state within the U.S. may move at any time to and take up residence in any other state only needing to sign the local state affidavit.
Any person may give up residence in the U.S. and move to another country without penalty or question as long as there are no outstanding legal issues having to do with causing harm to others, infringement of other's rights or breach of contract.
In relation to my position on government entitlement programs or other government subsidized programs, no one shall receive entitlements or subsidies because there will be none. The federal government will be focused in my administration to the stewardship and protection of individual's rights and ensuring the general welfare by making sure that all people have equal access to necessary natural resources. My administration will work to make sure that people will be able to make a living according to their self determined best interests without unnecessary interference from the government, religious or social organizations or other individuals.
My administration will not guarantee anyone's success or failure. I will not encourage the federal government to engage in choosing winners or losers. By taking residency in the U.S., responsibility for each individual's success, safety or protection from one's own decisions is assumed by that individual.
My administration will defend every individual lawfully taking residence within the U.S. and will defend and protect said individuals from threats from foreign countries, organizations and individuals who would threaten or violate an individual resident's life, safety, rights, or property.