#1. Genesis

N. 1 The provision on the bicameral system and the differences settlement procedure has its roots in the Constitution of 1848, which anchored the parity structure of the Federal Assembly as an expression of the federalist compromise. The Message on a new Federal Constitution of 20 November 1996 (BBl 1997 I 1) emphasised that the bicameral system «belongs to the supporting structural elements of Swiss federalism».

N. 2 The revision within the framework of the constitutional revision of 1999 introduced no substantive changes, but merely modernised the language. However, the explicit constitutional basis for the statutory regulation of the differences settlement procedure in para. 3 was newly included, which constitutionally secured the already existing parliamentary practice (BBl 1997 I 341).

#2. Systematic classification

N. 3 Art. 156 FC stands systematically in the section on the Federal Assembly (Chapter 3, Section 1) and concretises the bipartition of Parliament anchored in → Art. 148 FC. The provision is closely linked with → Art. 157 FC (Joint deliberations in special cases) and forms the basis for the implementing provisions in the Parliament Act (SR 171.10).

N. 4 In the context of the legislative procedure (→ Art. 163–165 FC), Art. 156 FC ensures that both chambers are involved as equal actors in the law-making process. This manifests the fundamental federalist character of the Federal Assembly, in which people (National Council) and cantons (Council of States) are equally represented (→ Art. 150 FC).

#3. Elements of the provision / Normative content

N. 5 Separate deliberations (para. 1): The principle of separate deliberation means that the National Council and Council of States hold their sessions separately and deliberate independently of each other. According to Ehrenzeller/Schindler/Schweizer/Vallender (St. Galler Kommentar BV, 4th ed. 2023, Art. 156 N. 3), this is an expression of the full equality of both chambers and prevents the dominance of one council.

N. 6 Agreement (para. 2): The consensus principle requires the substantive agreement of both councils for every Federal Assembly decree. According to one view in the literature, a mere majority in a combined parliament does not suffice, but identical decisions by both chambers are required. This applies to acts, ordinances of the Federal Assembly, federal decrees and simple federal decrees (→ Art. 163 FC).

N. 7 Differences settlement procedure (para. 3): The Constitution obliges the legislature to provide for a procedure that enables a solution in case of disagreements. The areas listed in lit. a–d are exhaustive according to Tschannen (in: St. Galler Kommentar BV, Art. 156 N. 12), which means that in other areas a blockade by one council remains possible.

#4. Legal consequences

N. 8 No decision-making without consensus: As long as the councils do not adopt matching decisions, no valid Federal Assembly decree comes into being. According to Häfelin/Haller/Keller/Thurnherr (Schweizerisches Bundesstaatsrecht, 10th ed. 2020, N. 1423), a council can cause any business to fail definitively through persistent rejection, unless the exceptions of para. 3 apply.

N. 9 Parliament Act as implementing provision: Art. 156 para. 3 FC is concretised by Art. 89–95 ParlA. The ordinary differences settlement procedure provides for a maximum of three deliberations per council. If the councils cannot agree, a conciliation conference is convened (Art. 93 ParlA).

N. 10 Accelerated procedure for special cases: For the matters mentioned in para. 3, a special procedure according to Art. 94 f. ParlA applies, which ultimately forces a decision. In the case of the declaration of validity of popular initiatives or the budget, no deadlock situation may arise, which is why special rules apply here.

#5. Disputed issues

N. 11 Scope of the consensus principle: The extent to which the requirement of agreement reaches is disputed in doctrine. While Rhinow/Schefer/Uebersax (Schweizerisches Verfassungsrecht, 3rd ed. 2016, § 15 N. 42) advocate a strict interpretation, according to which any difference, even purely editorial, excludes agreement, Graf/Theler/von Wyss (Parlamentsrecht und Parlamentspraxis, 2014, § 23 N. 15) argue for a more pragmatic view that tolerates insubstantial deviations.

N. 12 Justiciability of procedural rules: Whether and to what extent violations of Art. 156 FC are subject to judicial review is controversially discussed. Müller takes the position that gross procedural errors in the legislative procedure can lead to the invalidity of the enactment. The prevailing doctrine (Tschannen/Zimmerli/Müller, Allgemeines Verwaltungsrecht, 4th ed. 2014, § 28 N. 32), however, views parliamentary procedural rules as largely non-justiciable.

#6. Practical notes

N. 13 Tactical potential: The possibility of a council to block business through non-consideration or persistent rejection gives the smaller political groupings in the Council of States a de facto veto right. Parliamentarians should be aware of this power-political dimension.

N. 14 Significance of first deliberation: Since the council conducting the first deliberation shapes the basic structure of an enactment, the allocation for first deliberation has considerable practical significance. The presidencies of the councils coordinate informally on this to ensure a balanced distribution.

N. 15 Role of the conciliation conference: In practice, the conciliation conference composed on a parity basis (13 members per council each) almost always succeeds in finding a compromise. The conference members enjoy considerable scope and can propose package solutions that go beyond the original positions of the councils.

#Procedural References

Judgment 1P.853/2005 of 3.3.2006

Art. 156 para. 2 BV is mentioned in this decision in connection with the cost allocation in constitutional appeal proceedings. The Federal Court held that no costs should be imposed if the appellant prevailed (Art. 156 para. 2 BV).

«Bei diesem Verfahrensausgang sind keine Kosten zu erheben (Art. 156 Abs. 2 BV).»

However, the decision does not concern the substantive aspects of Art. 156 BV regarding parliamentary procedural rules.

Judgment 1P.559/2004 of 19.1.2005

In this proceeding concerning a cantonal municipal merger, Art. 156 para. 2 BV was likewise mentioned only in the context of cost allocation. The Federal Court confirmed that despite the appellant's defeat, no court costs should be imposed on her.

«Trotz des Unterliegens der Beschwerdeführerin sind ihr gemäss Art. 156 Abs. 2 BV keine Gerichtskosten aufzuerlegen.»

This decision also does not address the procedural rules of the Federal Assembly under Art. 156 BV.

#Lack of Justiciable Case Law

The small number of judicial decisions on Art. 156 BV is explained by the nature of the provision as an organisational rule for the Federal Assembly. The procedural matters regulated in Art. 156 BV (separate deliberation of the chambers, requirement of agreement, procedures for resolving differences) are primarily of a political nature and are given concrete form through the Parliamentary Act (ParlA).

Conflicts over the interpretation of procedural provisions are typically resolved within parliamentary practice or clarified by the parliamentary services. The justiciability of such disputes before the Federal Court is severely limited due to the separation of powers.

#Practical Significance

The practical application of Art. 156 BV occurs primarily through:

• The rules of procedure of both chambers
• The Federal Act on the Federal Assembly (ParlA)
• Parliamentary practice in resolving differences

Judicial control is limited to the few cases in which procedural errors by the Federal Assembly become relevant in subsequent legal protection proceedings, such as when challenging federal acts or federal decrees for violation of mandatory procedural provisions.