Modifies provisions relating to an income tax deduction for certain National Guard duties

HB 1233 modifies Missouri's income tax rules to allow taxpayers who serve in the National Guard or reserve components to deduct a growing percentage of their military income from their state taxable income. Starting in 2020, 20% of qualifying military income (including inactive duty training, annual training, state duty, or joining bonuses) could be deducted, increasing incrementally to 100% by 2024. This deduction applies only to income already included in federal adjusted gross income and excludes civilian federal service pay. The bill directly affects Missouri National Guard and reserve military members who file state tax returns.