Legislative power is divided between the federation and the state level. The Basic Law presumes that all legislative power remains at the state level unless otherwise designated by the Basic Law itself.

Any federal law overrides state law if the legislative power lies at the federal level. A famous example is the purported Hessian provision for the death penalty, which goes against the ban on capital punishment under the Basic Law, rendering the Hessian provision invalid. The Bundesrat is the federal organ through which the states participate in national legislation. State participation in federal legislation is necessary if the law falls within the area of concurrent legislative power, requires states to administer federal regulations, or is so designated by the Basic Law. Every state has its own constitutional court. The Amtsgerichte, Landgerichte and Oberlandesgerichte are state courts of general jurisdiction. They are competent whether the action is based on federal or state law.

Many of the fundamental matters of administrative law remain in the jurisdiction of the states, though most states base their own laws in that area on the 1976 Verwaltungsverfahrensgesetz (Administrative Proceedings Act) covering important points of administrative law. The Oberverwaltungsgerichte are the highest level of administrative jurisdiction concerning the state administrations, unless the question of law concerns federal law or state law identical to federal law. In such cases, final appeal to the Federal Administrative Court is possible.

Germany's military, the Bundeswehr, is a military force with Heer (Army), Marine (Navy), Luftwaffe (Air Force), Zentraler Sanitätsdienst (Central Medical Services) and Streitkräftebasis (Joint Support Service) branches. Military service is compulsory for men at the age of 18, and conscripts serve nine-month tours of duty. Conscientious objectors may instead opt for an equal length of Zivildienst (roughly translated as civilian service), or a six year commitment to (voluntary) emergency services like a fire department, the Red Cross or the THW. In 2003, military spending constituted 1.5% of the country's GDP. In peacetime, the Bundeswehr is commanded by the Minister of Defence, currently Karl-Theodor zu Guttenberg. If Germany went to war, which according to the constitution is allowed only for defensive purposes, the Chancellor would become commander in chief of the Bundeswehr.

The Bundeswehr employs 200,500 professional soldiers, 55,000 18–25 year-old conscripts who serve for at least nine months under current rules, and 2,500 active reservists at any given time. Roughly 300,000 reservists are available to the Armed Forces and participate in defense exercises as well as deployments abroad. Since 2001 women can serve in all functions of service without restriction, but they are not subject to conscription. There are presently around 14,500 women on active duty and a number of female reservists who take part in all duties including peacekeeping missions and other operations. Two female medical officers have been promoted to a General rank so far.

As of November 2009, the German military had about 8,300 troops stationed in foreign countries as part of various international peacekeeping forces, including 2,470 Bundeswehr soldiers in Kosovo, 4,520 German troops in the NATO-led ISAF force in Afghanistan and Uzbekistan, and 450 troops with UNIFIL in Lebanon.

In 2009, Defense Minister Karl-Theodor zu Guttenberg stated that conditions in Afghanistan were "like a war", while it previously had been referred to as "stabilisation and civilian reconstruction", avoiding the word "war".

The Judiciary of Germany is independent of the executive and the legislative branches. Germany has a civil or statute law system that is based on Roman law with some references to Germanic law. The Bundesverfassungsgericht (Federal Constitutional Court), located in Karlsruhe, is the German Supreme Court responsible for constitutional matters, with power of judicial review. It acts as the highest legal authority and ensures that legislative and judicial practice conforms to the Basic Law for the Federal Republic of Germany (Basic Law). It acts independently of the other state bodies, but cannot act on its own behalf.

Germany's supreme court system, called Oberste Gerichtshöfe des Bundes, is specialised. For civil and criminal cases, the highest court of appeal is the Federal Court of Justice, located in Karlsruhe and Leipzig. The courtroom style is inquisitorial. Other Federal Courts are the Federal Labour Court in Erfurt, the Federal Social Court in Kassel, the Federal Finance Court in Munich and the Federal Administrative Court in Leipzig.

Criminal law and private law are codified on the national level in the Strafgesetzbuch and the Bürgerliches Gesetzbuch respectively. The German penal system is aimed towards rehabilitation of the criminal; its secondary goal is the protection of the general public. To achieve the latter, a convicted criminal can be put in preventive detention (Sicherungsverwahrung) in addition to the regular sentence if he is considered to be a threat to the general public. The Völkerstrafgesetzbuch regulates the consequences of crimes against humanity, genocide and war crimes. It gives German courts universal jurisdiction if prosecution by a court of the country where the crime was committed, or by an international court, is not possible.

Law enforcement in Germany is constitutionally solely vested in the states, which is one of the main features of the German political system. Therefore, unlike France, Italy, the United States, Canada or many other countries, Germany has no federal police force comparable to the Carabinieri, Police Nationale, FBI or RCMP. Police has always been a responsibility of the German states and was continued after 1871 when the country was unified. The constitution of the Weimar Republic 1919 eventually did provide for the possibility to create a national police force, should the necessity arise, but it was only in the Nazi era, that a national secret police force (Gestapo) was created and the state police forces were unified under a central leadership. The police became a tool of the centralized state and the Nazi party. Following the defeat of 1945, Germany was divided; in 1949 the three western zones were turned into the Federal Republic of Germany (West Germany), the eastern zone became the German Democratic Republic (East Germany). Each country pursued a different path concerning law enforcement.

In light of the gross misuse of power by the centralized Nazi state the new constitution of the West Germany provided for a strict separation of powers, placing law enforcement firmly into the hands of the states. The only policing allowed on the federal level was border control (Bundesgrenzschutz including coast guard), controlled by the Ministry of Interior and originally organized along paramilitary lines, the Federal Criminal Police Office and the Police of the parliament.

East Germany created a new centralized police force under the Ministry of Interior, the paramilitary Volkspolizei. It also established a border police, initially an independent force, then integrated into the army and then reorganized as an independent military organization.