Although not a common defense, Missouri permits a defending party in a lawsuit to raise a defense that “there is another action pending between the same parties for the same cause in this state.” See Rule 55.27.
This defense — a/k/a abatement or the pending action doctrine — applies “where a claim involves the same subject matter and parties as a previously-filed action so that the same facts and issues are presented.” Estate of Holtmeyer v. Piontek, 913 S.W.2d 352, 357 (Mo. Ct. App. 1996). It “does not apply unless the issues are the same, and the alignment and identity of the parties is identical.” Kelly v. Kelly, 245 S.W.3d 308, 314 (Mo. Ct. App. 2008). Furthermore, abatement “does not apply to cases pending concurrently by the same parties in the courts of different states.” Welch v. Contreras, 174 S.W.3d 53, 56 (Mo. Ct. App. 2005); Rule 55.27(a)(9) (it must be an “action pending between the same parties for the same cause in this state”).