Mo. Rev. Stat. § 456.5-503: Exceptions to spendthrift provision.

1. In this section,

(1) "Child" includes any person for whom an order or judgment for child support has been entered in this or another state, and

(2) "Judgment" means a judgment which may be executed in this state.

2. Even if a trust contains a spendthrift provision, a beneficiary's child, spouse, or former spouse who has a judgment against the beneficiary for support or maintenance, or a judgment creditor who has provided services for the protection of a beneficiary's interest in the trust, may obtain from a court an order attaching present or future trust income. If there is more than one permissible distributee, the court may grant relief as is equitable under the circumstances.

3. A spendthrift provision is unenforceable against a claim of this state or the United States to the extent a statute of this state or federal law so provides.