Facts
The parties are married and have two common children ([C.] , born 2012, and [D.] , born 2015). They have been living separately since 1 May 2018. In the protection of marriage proceedings, the Basel-Landschaft Ost District Civil Court placed the children in the custody of the mother ([A.] , appellant) and, by order of 27 August 2018, ordered the father ([B.] , respondent) to pay child maintenance contributions of a total of approximately CHF 996.-- and CHF 993.-- respectively per child (direct maintenance and care maintenance). The agreement of 22 January 2019 confirmed these contributions.
On 13 December 2019, the father applied for a modification of these maintenance contributions with effect from 1 January 2020. The court provisionally set the maintenance at CHF 211.-- plus child allowances; the mother's legal remedies were unsuccessful (judgment 5A_536/2020). The municipality of [V.] partially advanced the maintenance contributions and was recognised as a party to the proceedings.
On 30 April 2020, the mother filed a divorce action with the Bern-Mittelland Regional Court and simultaneously applied for provisional determination of child maintenance. By judgment of 7 July 2020, the District Civil Court set the maintenance at CHF 341.-- (until 31 October 2020) and CHF 578.-- (from 1 November 2020) per child.
The Basel-Landschaft Cantonal Court (decision of 22 December 2020) partially upheld both appeals, set the maintenance contributions anew, and found a shortfall between March and October 2020. It affirmed its jurisdiction even after the divorce proceedings had become pending, but limited the consideration of facts to those before 30 April 2020 and excluded exhibits relating to the period thereafter from the file.
The mother filed a civil law appeal or, in the alternative, a subsidiary constitutional complaint with the Federal Supreme Court, requesting in the alternative the determination of higher maintenance contributions and in the main the dismissal of the application for reduction. The father requested non-admission, or alternatively dismissal. The municipality did not submit a statement. The Federal Supreme Court obtained the cantonal files. The main question was whether the marital protection court had jurisdiction after the divorce proceedings became pending and whether it should have taken into account facts that arose subsequently.
Considerations
The appeal is directed against a final decision of a last cantonal instance on the modification of child maintenance in protection of marriage proceedings (Art. 90 FSCA, Art. 179 para. 1 and Art. 176 para. 1 no. 1 CC). Since decisions on the modification of protection of marriage orders are deemed provisional measures (Art. 98 FSCA), only the violation of constitutional rights may be claimed, whereby the strict principle of complaint under Art. 106 para. 2 FSCA applies. The mother has standing to appeal. The municipality, which advanced the maintenance, is not a party, because in the case of advance payment only the individual maintenance claims are subrogated, not the underlying right itself; passive legitimation in modification proceedings lies with the child or its representative (judgment 5A_75/2020 consid. 6). The father, who did not himself file an appeal, may only defend the result of the cantonal decision, but cannot obtain a change in his favour (prohibition of reformatio in peius, Art. 107 para. 1 FSCA).
Exhibit 2 (rental agreements) was already submitted in the cantonal proceedings and may be filed again. Exhibit 3 (criminal court judgment of 19 January 2021) is an inadmissible genuine novum, but may be taken into account in connection with procedural aspects (legal aid).
On jurisdiction: under Art. 276 para. 2 CPC, protection of marriage measures remain in force until the divorce court modifies them. The initiation of divorce proceedings neither renders the protection of marriage proceedings moot nor results in the loss of jurisdiction of the marital protection court (BGE 138 III 646 consid. 3.3.2). The Federal Supreme Court clarifies that the contrary statement in judgment 5A_139/2010 is based on an erroneous reproduction of the case law. Since the divorce court had not yet ordered any provisional measures, the marital protection court had jurisdiction and could make a regulation without temporal limitation. There is no violation of Art. 30 para. 1 Cst.
On arbitrariness in considering subsequent facts: the complete disregard of facts and evidence arising after the divorce proceedings became pending, in protection of marriage proceedings, is manifestly untenable (judgment 5A_294/2020 consid. 4). The marital protection court must conclude the proceedings, including all facts and evidence to be considered under Art. 229…