Because it is established by a Federal law (the " Soldiers and Sailors Relief Act "), rather than state law, we regularly encounter questions regarding the taxablility of cars owned by military personnel, including their spouses.

The Federal Law specifies that persons in the military are subject to property taxes on their motor vehicles only in the county and state from which they entered service, unless they establish permanent residence elsewhere.  Registration  of their cars has nothing to do with their taxability here or elsewhere.  (Registration is only a method of requiring that taxpayers list their cars for taxation - it does not relate to liability for taxes.) If a car is registered to the serviceman or woman in joint registration with their spouse or someone else, it still falls under the taxable situs of the Soldiers and Sailors Relief Act. 

The change in the Federal Law (Military Spouses Residency Relief Act) now requires a vehicle (or, other personal property) not to be taxed in Missouri if it is owned by the spouse of a service member whose home of record is not Missouri, and whose residence is the same as the service member’s, even if the property is owned individually by the spouse. Conversely, personal property is taxable in Missouri if it is owned by the spouse of that service member stationed outside the state of Missouri but whose home of record is Missouri, even if the property is located outside Missouri, provided the residence of the spouse is the same as the service member’s. 

The assessment of military personnel continues to be an area of confusion, judging from the number of calls we receive on this subject.  The law in this area is controlled by the federal Soldiers and Sailors Relief Act of 1940 and the Military Spouses Residency Relief Act.  The United States Supreme Court has stated that military personnel shall not lose their residence or domicile in their home state solely because they are absent from the state in compliance with military or naval orders.  However, military personnel (and/or their spouses) stationed away from Missouri still must pay personal property taxes in Missouri assuming they retain Missouri as their State Home of Record (HOR) or have Missouri as their State of Legal Residence (SLR).

The military personnel (and/or their spouses) are treated as though they never left their homestate and county.  Consequently, assessors should treat the tangible personal property of Missouri personnel (and/or their spouses) stationed in other states or countries the same as if the taxpayer is living in the county and the personal property is present in the state.  The other side of the matter, is that the personal property of any [non-resident] individuals residing in your county by means of military orders are not taxable in your jurisdiction, with the exception of business personal property located in Missouri and owned by non-resident military personnel.

The Attorney General issued an opinion [Burrell, Op. Att'y Gen. No 95 (Feb 16, 1966)] concluding that non-resident military personnel stationed in Missouri may obtain a certificate of no tax due (a waiver) from the collector and license their cars in Missouri without paying property tax on them. 

If the vehicle is registered jointly with a non-resident military person and their military spouse, or the non-resident military spouse is the sole owner, the vehicle may not be taxed in Missouri.

Verification of the home of record (or State of Legal Residence) is easily ascertainable by looking at the bottom portion of the "Leave and Earnings Statement" (i.e. pay stub) which indicates the individual's claimed home state of record; the State to which income taxes are being paid to.