In the past, the liberals, as they're also known, were part of conservative-led coalitions under chancellors from Konrad Adenauer to Helmut Kohl to Merkel herself.
But being centrists, the Free Democrats also have nothing per se against cooperating with the Social Democrats. The FDP was part of governing coalitions under Social Democrat chancellors Willy Brandt and Helmut Schmidt. There is considerable resistance in Germany toward the Social Democrats doing a deal with the Left party, the successor to the socialist party in communist East Germany. So, the SPD under Martin Schulz might not have any other option than to make a pact with the FDP and the Greens.
The party's flexibility means that its charismatic young chairman Christian Lindner could hold the keys to the chancellor's office. With his choice of a political partner, he could make either Martin Schulz or Angela Merkel chancellor.
If they're so important, how come I've heard so little of them recently?
The FDP was represented in parliament for 64 straight years but failed to clear the 5-percent hurdle in 2013 and lost all its seats in the Bundestag, the German parliament. That debacle was the result of weak leadership and the widespread perception that the party was interested only in holding power, not enacting any concrete policies. The 38-year-old Lindner is trying to overcome that image and has pointedly refused to identify potential coalition partners, stressing political positions instead.
Okay, so what does the FDP want to do?
The Free Democrats are liberals in two senses of the word. They take a laissez-faire approach to government's relationship with business and have an unshakable faith in the free-market economy. They're also liberal democrats who think that the state should interfere as little as possible in the lives of individuals. So much for their general orientation.
The FDP platform approved by the party conference on April 30 is a decidedly mixed bag, stressing two topics: digitization and education. The Free Democrats are promising to improve Germany's mediocre digital infrastructure and create a new Ministry of Digital Affairs, and to invest more in schools and universities. These are hardly classic laissez-faire positions, but who doesn't enjoy high-speed internet surfing and learning useful skills?
And those aren't the only contradictions between the party platform and a traditional liberal outlook. The Free Democrats support dual citizenship, in opposition to the conservative CDU-CSU, but want to force third-generation immigrants to choose one nationality. Lindner has criticized the Merkel government for its handling of the refugee crisis, saying people were inadequately vetted and calling for speedier deportations of those whose asylum requests are rejected.
The traditionally affluent FDP constituency will be happy about promises to push for tax cuts amounting to €30 billion ($32.7 billion). On that score at least, this iteration of the Free Democrats remains true to the party's past.
Speaking about the past, wasn't there something about skydiving?
The FDP's history is full of changes of fortune. For decades, the Free Democrats were part of governments of various political stripes. The FDP emphasized its power as kingmaker in 1982, when its ministers abandoned Social Democrat chancellor Schmidt and enabled the rise of the conservative Kohl. FDP Foreign Minister Hans-Dietrich Genscher, together with Kohl, was one of the main architects of German reunification after the fall of the Berlin Wall in 1989.
But party fortunes turned south after that historic highpoint. With the election of the SPD-Green coalition under Gerhard Schröder in 1998, the FDP found itself outside the government for the first time in 29 years. A younger generation of leaders, including Guido Westerwelle and Jürgen Möllemann, tried to remake the FDP as a "party of fun." Westerwelle appeared on the reality show Big Brother and targeted 18 percent for the next election, but the Free Democrats missed that goal by a mile. Amidst a campaign contributions scandal, the passionate skydiver Möllemann would later apparently commit suicide by jumping from an airplane and not pulling his parachute rip cord.
In 2009, profiting from dissatisfaction with Merkel's first grand coalition, the FDP under Westerwelle got 14.6 percent of the vote and rejoined the government. But everything did not go smoothly.
Westerwelle became a much-criticized foreign minister, infamously instructing a BBC journalist to speak German in his first press conference. It was the first of many uncomfortable incidents in his tenure in the post. Support for the party drained precipitously; the FDP dropped out of one local parliament after another. Under the tepid leadership of Philipp Rösler, the party polled only 4.8 percent in the 2013 national elections. After that debacle, Lindner took charge. Westerwelle died of leukemia in 2016.
So how did they manage their revival?
The Free Democrats have the man, but do they have the message? In Lindner, the FDP is led by a figure who is both media-friendly and credible, but the party lacks a single clear issue that people can get behind. Lindner single-handedly brought about the FDP's victory in Germany's most populous state, North-Rhine Westphalia in May - and if history is any lesson, they profit from a measure of electoral fatigue.
The traditional enmity between the Green Party and the Free Democrats runs deep - the FDP has never forgiven the Greens for usurping its status as Germany's third political power.
But the chance to wield political makes for marriages of convenience; many political observers believe that the resurrected FDP and the Greens will play a role in a future government.Jefferson Chase