The liberal Free Democratic Party's defeat on election night was resounding and painful. "It was the bitterest hour for the FDP," said Christian Lindner, the party's former general secretary, as the first projections were published.

With 4.8 percent, the party was well below the 5 percent needed to enter parliament, and 10 percent below their showing in 2009. For the first time since 1949, the liberals will not be represented nationally.

Lindner, an otherwise eloquent speaker, struggled through his first TV interview of the evening. Viewers could clearly see his disappointment. In 2009, the FDP had its best electoral showing in post-war German history, winning 14.6 percent of the vote. But now they have suffered an unparalleled defeat, going from a record high to a record low in just one election cycle.

"It was the receipt for their policies," political scientist Ulrich von Alemann told DW. "The FDP made mistakes in their politics, platform, and campaign as well as among their leading personalities."

Tainted by special interests

A legislative period lasts four years in Germany. For the FDP, the past four years were a series of initial ups followed quickly by major downs. The descent began shortly after the 2009 election.

The FDP, with support from the Bavarian CSU, pressured Merkel's government into reducing the sales tax for the hospitality industry. Shortly thereafter, it became known that the FDP had received a donation of millions of euros from the industry.

"The FDP immediately stood there as a clientele party; as a party of special interests that wanted to make life easier for those who pay the most taxes," von Alemann said.

Bitter personnel battles also hurt the party's image. Due to plummeting poll numbers, Foreign Minister Guido Westerwelle was forced to resign as vice chancellor and party chairman in 2011. But the new FDP chief, Philipp Rösler, proved unable to reverse the negative trend.

The Free Democrats reached a low point during the 2012 regional elections in the Saarland, when they won only 1.2 percent of the vote. It was the FDP's worst election showing in a western German state since the party's founding.

Successes largely personality driven

The party did manage to book some successes on the state level, above all when the candidates distanced themselves from the national party.

Christian Lindner helped the FDP win 8.6 percent of the vote in North Rhine-Westphalia. Likewise, Wolfgang Kubicki secured 8.2 percent of the vote for the Free Democrats in Germany's northernmost state of Schleswig-Holstein.

The party's victories in North Rhine-Westphalia and Schleswig-Holstein were largely due to voters' personal affinity for Lindner und Kubicki. But popular figures were sorely missed on the national level. Guido Westerwelle has been increasingly recognized for having grown into the office of foreign minister.

"But in terms of foreign policy, he doesn't have anything to show where one would say: yeah sure, foreign policy, Westerwelle achieved this and that," von Alemann said.

Once a Kingmaker

The FDP has a wealth of experience when it comes to being in government - not even the CDU/CSU has been in more administrations. In the 64-year history of post-war Germany, the Free Democrats formed part of the government for 52 years. The CDU/CSU was in power for just 44 years.

The FDP governed continuously from 1969 until 1998 with alternating coalition partners, first with the Social Democrats and then with the CDU. No other party has governed continuously for as long as the Free Democrats. But they were always the junior partner.

Votes lost to other parties

As a small party, the FDP was fighting an uphill battle from the start on Sunday.

"Merkel's strength doomed the FDP," von Alemann said. "The magnitude of their loss can be attributed first and foremost to Chancellor Merkel and the CDU."

The FDP's success in 2009 was largely due to swing voters, who were disappointed with the grand coalition, particularly with the CDU. But those voters moved on, casting their ballots for other parties this time around.

According to von Alemann, the euro-skeptic Alternative for Germany (AfD) party also siphoned off critical votes from the FDP: "Without Alternative for Germany, the FDP certainly would have made it into parliament."

The pre-election polls had already indicated that the Free Democrats might be kicked out of the Bundestag. Their numbers had been hovering between 4 and 6 percent.

And then, a week before the federal election, the FDP failed to win representation in Bavaria. In Hessen, which held its state elections together with the federal poll on Sunday, the liberals barely made it into the state parliament.

The FDP's future

So is it time to say goodbye? Not quite yet, according to von Alemann.

"The FDP is tough," he said. "They have a deep history. They have representatives all over the country, including in the municipalities. They are deeply anchored in society, in the public - so it's not yet the end of the FDP."

But the fiscally conservative and socially liberal wings of the party need to be brought back into harmony with one another, according to von Alemann. Christian Lindner might be just the man to reconnect the two groups. The defeat on Sunday was so fundamental and so profound, that "starting tomorrow the FDP needs to be rethought," Lindner said.

The Free Democrats' rehabilitation will be difficult. But they have four years time - until the next federal election.