In many countries, a strong lead for a party in opinion polls often entails a landslide victory, but things are not that simple in Germany's electoral system. The system is described by many as complex. 

The front-runner Olaf Schulz, the current Vice-Chancellor and Finance Minister, may be forced to ally with any potential partners to succeed Angela Merkel as head of the chancellery.

The reason for this goes back to West Germany's post-war electoral system, which blends a winner-takes-all majoritarian approach as in the UK and the United States, with a proportional representation system that makes room for smaller parties. 

German voter corps composition

A total of 60.4 million people over 18 are entitled to vote in the upcoming elections. They will choose the next government in the European Union's most populous country and largest economy. 

Women voters outnumber men, with 31.2 million female voters, compared to 29.2 million male voters. Among them, about 2.8 million will vote for the first time on Election Day, September 26.

Four years ago, voters' turnout reached 76.2%, an increase of about 5 points compared to the 2013 elections, and higher than the turnout registered in many other elections taking place in Western countries.

This year, 33% of the candidates for the German Federal Parliament (Bundestag), which eventually elects the chancellor, are women. It is a record number in the post-war period.

Forty-seven parties are participating in the elections with candidates, which is also a precedent.

The 5% threshold

Entering the voting booth, the German voter will have to mark on the ballot paper two times; the first to choose his direct representative in the local district, and the second to choose his preferred political party.

The purpose of the first vote is to ensure that all 299 German districts are represented in the Bundestag through a single-member district system. In the second vote, which is considered decisive in many aspects, the citizen chooses a party on the Federal level.

Ahead of Election Day, parties submit slates of candidates in all 16 states. The names at the top of the list have the highest chance of winning a seat. Then the party with the most votes sends the largest number of legislators to the Federal Parliament.

Furthermore, parties are entitled to additional seats if the result they get in the second proportional voting surpasses their score in the first one. To simplify it, for example, if party A wins 3 seats directly from the first vote, but is entitled to 10 seats in the second vote, 7 other names in the state represented by the party are also given seats.

The Bundestag could be extended

Complexity arises when the results of Majoritarian voting (first vote) do not match the results of proportional voting (second vote), which happens when voters split their votes.

Contrarily, if party B obtains in the first vote more seats than it is entitled to through the second vote, the additional seats stay as part of party B's share anyway. Those seats are called "overhang".

As a result, the size of the Bundestag could become much larger than its minimum 598 seats. After the 2017 elections, the number of legislators reached 709.

Parties that do not reach the 5% threshold in the second vote do not enter Parliament. The purpose of this threshold is to prevent excessive political fragmentation and to prevent the arrival of potentially 'extremist' parties.

The question of the left-wing Die Linke party reaching the 5% threshold is still on the line. Its success or failure may be a major factor in the calculations of post-election alliances.

The most important question when polls are closed will be whether any party alliance has achieved an absolute majority that permits it to nominate a chancellor, i.e. half the seats of the Bundestag plus one.

SPD is registering a decline but still leading in polls

An opinion poll carried out by Kantar indicated a decrease in the level of support for the Democratic Socialist Party (SPD) of one point and is now at 25%, and a one-point increase in support of the Christian Social Union and Christian Democratic Union alliance (CDU-CSU), amounting to 22%.

The SPD is led by Olaf Scholz while the CDU is led by Armin Laschet. The two leaders will be competing for the chancellery.