Rule 33.Third-Party Rights and Other Claims in an Existing Action

Rule 33 is a routing rule. Family law has two intervention routes of its own; everything else borrows from civil practice.

The two family law routes

Third party rights. A person other than a legal parent may petition to intervene in an existing action under A.R.S. section 25-409 -- the statute governing in loco parentis standing, visitation and placement claims by grandparents and other non-parents.

The State. The State may intervene in an existing action under A.R.S. section 25-509, which is how a Title IV-D child support matter joins a private case.

Everything else

Section (c) sends any other request -- a counterclaim, a third-party claim, joinder of parties, interpleader, or intervention -- to the procedures in Arizona Rules of Civil Procedure 13, 14, 18, 19, 20, 21, 22 and 24.

This is worth pausing on, because Rule 1 makes the civil rules apply only where these rules expressly say so. Rule 33(c) is one of the express places. A counterclaim in a family law case is governed by Civil Rule 13, not by anything in this ruleset -- and a practitioner who looks only here will not find the standard.

The cross-reference that matters elsewhere

Rule 29(g)(2) preserves, until trial, the defense of failure to join a person required by Rule 33(c). Because 33(c) points to Civil Rule 19, the required-party standard in an Arizona family law case is the civil one.