The first Luther cabinet, headed by the politically independent Hans Luther, was the 12th democratically elected government of the Weimar Republic. It took office on 15 January 1925, replacing the second cabinet of Wilhelm Marx, which had resigned when Marx was unable to form a new coalition following the December 1924 Reichstag election. Luther's cabinet was made up of a loose coalition of five parties ranging from the German Democratic Party (DDP) on the left to the German National People's Party (DNVP) on the right.

The cabinet's primary achievement was negotiating the Locarno Treaties and then seeing them approved by the Reichstag. The main pact secured Germany's post-World War I borders in the west with the stipulation that it not use force to change them.

The DNVP, the largest parliamentary party in the coalition, withdrew from the cabinet on 26 October 1925 in protest against the Treaties. Four days after they were formally signed on 1 December, Luther resigned with his cabinet in order to try to rebuild a majority government. The cabinet remained in office in a caretaker capacity until he formed his second cabinet on 20 January 1926.

Establishment

Attempts to form a new government began when the second Marx cabinet resigned on 15 December 1924. Marx had been asked by German President Friedrich Ebert to build a new coalition, but he found the goals of the parties incompatible, and including the whole spectrum from the leftist Social Democrats (SPD) to right-wing German National People's Party (DNVP) did not succeed. The refusal of the German Democratic Party (DDP) to work with the DNVP also ruled out a broad "bourgeois" coalition. As a result, Marx gave up on 9 January. Hans Luther, an independent, began talks on 10 January, but his initial attempt to form a coalition failed when the Centre Party asked for reassurance that the DNVP would accept a formal declaration of allegiance to the democratic constitution. When Luther was unable to provide one, the plans fell through.

Luther then initiated a second round of negotiations aimed at setting up an alternative to the traditional party-based cabinet. The idea was for the DNVP, Centre Party, German People's Party (DVP) and Bavarian People's Party (BVP) each to appoint a representative who would not be formally bound by party discipline. They would be joined by several technocrats, who – although nominally without party affiliation – would be vetted based on the closeness of their views to those of the political parties involved. The half way construct between a purely technocratic government and one based on a coalition of parties would, so Luther hoped, make it easier for the parties not included to support its policies in the Reichstag. Since the SPD had expressed its opposition to a bourgeois government, Luther apparently was trying to win the support of the DDP.

The Centre Party was willing to support the new cabinet only if the DDP agreed to keep Otto Gessler (DDP) in office as Reichswehr minister. Luther was able to get an agreement from the DDP's Erich Koch-Weser the next day. The issue that remained to be settled at that point was the form in which the cabinet should gain the necessary expression of support of the Reichstag. On 15 January, it became obvious that a formal vote of confidence, as preferred by the DNVP, was viewed unfavourably in the Centre Party parliamentary group. The parties then agreed to settle for a vote of acknowledgement on the government declaration. The same evening, Luther was appointed chancellor.

The complete cabinet was presented to the public on the day of the government declaration, 19 January 1925. Four parties contributed a representative: DVP (Gustav Stresemann), Centre Party (Heinrich Brauns), DNVP (Martin Schiele) and BVP (Karl Stingl). Schiele, a member of the Reichstag since 1914 and head of the DNVP parliamentary group since late 1924, was the only one among them without previous government experience. Of the four, only Stingl was not a member of the Reichstag. Two ministries were awarded to technocrats not directly associated with a party's parliamentary group: Otto Gessler at the Ministry of the Reichswehr, a DDP member but not in the Reichstag since 1924, and Gerhard von Kanitz at the Ministry of Food and Agriculture. Both had held the same offices in the previous government. The other portfolios were distributed between the coalition parties, and experts who were close to the parties were then appointed. Otto von Schlieben (DNVP) had previously headed the budget department at the Ministry of Finance, where he became minister. Albert Neuhaus (DNVP), a former head of the trade department of the Ministry of Economic Affairs who had left public service in 1920 when he refused to swear allegiance to the Weimar Constitution, became minister of Economic Affairs. The DVP nominated Rudolf Krohne, a state secretary at the Ministry of Transport, to become its minister. The Centre Party nominated Josef Frenken for Justice.

Members The members of the cabinet were as follows:

The DNVP ministers resigned from the cabinet on 26 October 1925 in protest against the signing of the Locarno Treaties.

Foreign policies In foreign policy, the cabinet had two main tasks. One was to establish normal trade relations with its European neighbours following the expiration on 10 January 1925 of the clause in the Treaty of Versailles that required Germany to grant them most favoured nation trade status. The second and larger issue was settling security arrangements in Europe. It was the latter issue which eventually resulted in the resignation of the DNVP ministers.

Security policy and the Locarno Treaties

In December 1924, at a meeting with French Prime Minister Édouard Herriot, British Foreign Secretary Austen Chamberlain expressed support for a separate treaty between France and Britain, outside of the wider European collective security arrangement that was sought by the League of Nations. Another problem from the German point of view was the decision by the Council of the League that, after the end of the military occupation of a territory (according to Article 213), the Council would be allowed to retain permanent observation institutions in the demilitarised zone. France was eager to pursue this and argued for its implementation in the Rhineland. The northern Rhineland zone was due to be vacated by the Allies on 10 January 1925. They refused to do so and on 5 January justified their decision in a note with vague references to German "breaches of the disarmament clauses of the Treaty of Versailles". Further instructions to Germany as to what was expected in terms of additional disarmament would follow.

As a result, Germany was forced to abandon its previous wait-and-see stance. It presented a secret memorandum on 20 January to Britain and on 9 February to France, suggesting a non-aggression pact between all countries "interested in the Rhine". It also offered a guarantee of the "current status on the Rhine" (i.e., the German-French and German-Belgian borders) and the signing of arbitration agreements with all interested parties. Luther and Foreign Minister Gustav Stresemann informed the rest of the cabinet of the full details of the note only two months later. They anticipated strong opposition from the DNVP and feared that a domestic debate would both undermine the government's position in negotiations with the Allies and threaten the government's cohesion.

During talks about the memorandum, Chamberlain demanded that Germany join the League with no conditions and as an equal partner. Although the German side agreed to a linkage between League membership and the security question, it stuck to its earlier position that as a disarmed and economically constrained country, it would require a special dispensation from Article 16 of the Covenant of the League of Nations, which forced all members to treat war on any other member as an act of aggression and respond with sanctions. More seriously, Chamberlain tried to win a German agreement that under no circumstances would they try to change the status quo on the German-Polish border through military means and accept it as permanent in the same way as the French-German border. This was steadfastly opposed in Berlin, where the cabinet insisted on leeway to change the border by peaceful means and saw the arbitration agreement proposed in the memorandum as sufficient.

By March, concerns started to surface in the DNVP about the government making too many concessions, and its parliamentary membership wrote to Stresemann indicating that they would not agree to any treaties unless the "spirit of the negotiations" changed. By throwing his personal weight behind the foreign policies, Luther was able to defuse the situation, and the DNVP members reduced their criticism to complaining about the secretive way in which the Foreign Office had acted. Luther promised greater transparency in the future and the involvement of party representatives. Stresemann said that the government would not change its stance on the Polish border and that he saw the current process leading towards a speedy withdrawal of foreign troops from Cologne and the Ruhr as well as their departure from the rest of the occupied Rhineland ahead of schedule.

At that point, the focus shifted to the disarmament issue. After the German government had sharply protested the Allied decision not to vacate the northern Rhineland and asked for an explanation, no further progress had been made. Through unofficial channels, the Reichswehr Ministry managed to gain access to some details of the report by the Military Inter-Allied Commission of Control (CMIC), but it remained unclear which of its findings served as the rationale for the refusal to withdraw. Meanwhile, with no official information available, the foreign press was starting to speculate about significant German breaches of the disarmament clauses, and indeed about secret preparations for war. When no Allied note had been received by mid-May, Stresemann strongly criticised the delay in a Reichstag speech and expressed his hope that any remaining issues the Allies might have would turn out to be minor.

On 4 June, Germany received the Allied response. It contained a surprisingly long list of German infractions, according to Stresemann, mainly "petty and pathetic" points. It also made a number of major demands on armament, organisation of the armed forces, and police or troop training that could not be reasonably derived from the Treaty of Versailles' articles. However, the northern Rhineland would be vacated as soon as all points had been cleared up. The cabinet faced a difficult choice: agree to the whole list in the interest of regaining control of the Rhineland, or offer to deal only with those points which were clearly based on Germany's obligations under the Treaty. On Stresemann's suggestion, the cabinet chose the second option and appointed a commission to negotiate with the CMIC.

On 16 June, France replied to the secret German memorandum. It agreed to negotiate a security pact, but demanded a full entry of Germany into the League and acceptance of arbitration agreements. They would be guaranteed by Great Britain, France, Italy and Belgium in the west and by all signatories of the Treaty of Versailles in the east.

Both Allied communications were made public on 19 June, causing a heated debate over Stresemann's policies. In the cabinet, Frenken, Neuhaus, von Kanitz and Schiele, plus Commander in Chief of the Army Hans von Seeckt, refused to support another voluntary confirmation of the western borders forced on Germany at Versailles. Stresemann refused to conduct further negotiations in such a way that they must fail, as suggested by Frenken. Luther supported his foreign minister, and the cabinet agreed on further talks with the Allies on the issues.