The Mexican government requires that tourists get auto liability insurance from a Mexico-based insurance company. Although your USAA auto policy may provide limited coverage for any loss or damage that occurs within a certain distance from the U.S.-Mexico border (check your policy for details), it doesn't provide the insurance legally required for travel in Mexico.
In the U.S., there are only two states where you’re not legally required to carry auto insurance: New Hampshire and Virginia. This, however, doesn’t mean you shouldn’t buy a policy if you live there. Additionally, this means that if you do not have auto insurance in Illinois, you’re not only risking financial trouble but you may also face legal consequences.
For serious accidents, you want enough insurance to cover a judgment against you in a lawsuit without jeopardizing your personal assets. Therefore, it's a good idea to have the same level of bodily injury coverage for all your cars. You may also want to consider an umbrella policy which provides additional coverage for more serious accidents and lawsuits.
Please note that this website provides only a summary of auto insurance, written to illustrate in general terms how auto insurance works. Your insurance policy is the legal contract that contains the terms and limitations of your coverage. You should carefully review the contents of your policy. All products and coverages are subject to availability and limitations. Whether an accident or other loss is covered is subject to the terms and conditions of your insurance policy.