Source (#1 and #2):
Andrew McClurg, David Kopel, and Brannon Denning.
Gun Control & Gun Rights. New York: New York University, 2002.
You have FOIDs because:
1) Barron v. Baltimore (32 US 243 (1833))
It ruled that The Bill of Rights only restrict Federal action and do not apply to state action. This idea is central to ALL laws regarding the regulation of rights in this country. Under this ruling, only the state constitutions enumerate rights and any limitations to those rights. Therefore, if the right to keep and bear arms does not exist in a constitution, then the citizens of that state do not have that right. Any law restricting arms is valid in such a state under the system as currently implemented.
2) SCOTUS policy of "selective incorporation" into the 14th Amendment to The Constitution.
This policy focuses upon the evaluation of a right on a case by case basis. SCOTUS decides whether or not a freedom is "sufficiently fundamental" to be included under 14th Amendment protection. They are answering the question of whether or not the right should be included under due process of law to make it binding on the states.
3) Illinois State Constitution:
SECTION 22. RIGHT TO ARMS
Subject only to the police power, the right of the individual citizen to keep and bear arms shall not be infringed.
Source:
http://www.ilga.gov/commission/lrb/con1.htm
The state constitution states your right to arms is subject to police power.
"In 1968, Illinois enacted legislation to promote and protect the health, safety and welfare of the public by providing a system of identifying persons who are not qualified to acquire or possess firearms and firearm ammunition within the State of Illinois. The Firearm Owner's Identification (FOID) Act established a practical and workable system to identify persons prohibited by Section 24-3.1 of the "Criminal Code of 1961" as amended, from acquiring or possessing firearms and firearm ammunition. The Illinois State Police was given the responsibility of administering the Act."
"There are approximately 1.2 million valid FOID card holders. Approximately 210,000-220,000 applications are processed annually by the Firearms Services Bureau. In 2002, 4,642 applications were denied and 6,926 FOID cards were revoked as a result of the extensive review process which identifies individuals whom are prohibited from possessing or acquiring firearms and firearm ammunition."
"All Illinois residents who buy or possess firearms are required by law to have a valid FOID card. FOID applications can be obtained from any firearm's dealer, law enforcement agency, or printed from the Internet. FOID cards are valid for 10 years from the date of issuance. To obtain a FOID card, complete an application and forward it along with a $10.00 fee and a photograph to the Illinois State Police, Firearm Owner's Identification Unit, Post Office Box 19233, Springfield, Illinois 62794-9233."
Source:
http://www.isp.state.il.us/foid/
What is the source of police power? The state. I think Presser v. Illinois applies. The following is my opinion (from an article I'm currently writing. The quoted ruling is from Kopel, et al.).
The 1833 decision in Barron v. Baltimore directly affected another SCOTUS decision in 1886 in Presser v. Illinois (116 US 252 (1886)). The central theme of the case surrounded Presser's violation of a state statute prohibiting groups of men from forming a military organization. As part of this ruling, the court ruled:
"The second amendment declares that it shall not be infringed, but this, as has been seen, means no more than that it shall not be infringed by congress. This is one of the amendments that has no other effect than to restrict the powers of the national government, leaving the people to look for their protection against any violation by their fellow-citizens of the rights it recognizes to...the 'powers which relate to merely municipal legislation, or what was perhaps more properly called internal police,' 'not surrendered or restrained' by the constitution of the United States...."
The court blatently states that we must rely upon police protection and that The Constitution does not apply (additional case law in all 50 states precludes the states from liability in case of police failure (6)). This directly contradicts the supremacy clause in Article VI. Additionally, the court has not incorporated the second amendment into the fourteenth amendment, though it certainly had the opportunity to do so in Heller v. DC.
Unfortunately, I think the police power bit has been stretched to include licensing. Even if it applied to Illinois, Heller supports this interpretation of the RKBA under Illinois' constitution. However, the license "...must be forthcoming". However, they have also seen fit to expand this power (not a right; states don't have rights, they have powers) to include bans on weapons. Fortunately, Heller does define a limit...but ONLY at the Federal level.
state! 
the nazi's must have moved to illinois after wwII.
