Although born only eight years apart, Donald Tusk and Jaroslaw Kaczynski could hardly be more different.

Opposition leader Donald Tusk (66) appears at campaign rallies in an open-necked white shirt with a red-and-white heart-shaped badge. The chairman of the liberal-conservative Civic Platform (PO) cuts a young, dynamic figure.

He speaks without notes and doesn't shy away from controversial topics. His campaign events are open to everyone — even political opponents, who often ask uncomfortable questions.

Jaroslaw Kaczynski (74), leader of the ruling Law and Justice (PiS) party, is his polar opposite. His events are heavily guarded by police, and attendance is restricted to selected functionaries and party supporters.

Dressed in a dark suit and tie, Kaczynski rattles off his speeches, which are largely full of warnings against Tusk and attacks on the nasty Germans. If questions are permitted, they are generally prepared in advance and read out.

Kaczynski avoids TV debate

In the run-up to this weekend's election, Tusk challenged his opponent to a television debate several times — to no avail. When Polish state television (TVP) finally broadcast a debate between party leaders on Monday, Kaczynski sent Prime Minister Mateusz Morawiecki to stand in for him, while he attended a campaign event in the provinces.

"Coward" was Tusk's reaction to his opponent's absence. The last time Tusk and Kaczynski faced off in a television debate was in 2007. Back then, Kaczynski fared very poorly.

Common ground and stark differences

As hard as it is to imagine now, Kaczynski and Tusk used to have quite a lot in common: For instance, both were active in the anti-communist opposition.

As far back as the 1970s, Kaczynski was a member of the Workers' Defense Committee (KOR).

As a student in Gdansk, Tusk supported the Solidarnosc (Solidarity) trade union right from the time it was set up in 1980.

A new start in a new Poland

The collapse of communism in 1989 opened up new prospects for both men. In line with his liberal leanings, Tusk founded the Liberal Democratic Congress (KLD), which was for a time even part of Jaroslaw Kaczynski's Christian Democrat Centre Agreement party. Soon, however, the two politicians went separate ways.

In 2001, both launched the two parties that continue to shape politics in Poland to this day: Jaroslaw Kaczynski and his twin brother, Lech, founded the Law and Justice (PiS) party, while Donald Tusk set up the Civic Platform (PO).

After the parliamentary election in 2005, the two parties entered negotiations to form a coalition government. Mistrust and ambition prevented them from reaching an agreement. This was the last time their paths crossed as potential political allies.

Since then, their parties have alternated at the helm of government: first Kaczynski's PiS (2005–2007), then Tusk's PO (2007–2014), and then Kaczynski's PiS again (since 2015).

Kaczynski partially blames Tusk for his brother's death

Over the years, however, the political rivalry between Tusk and Kaczynski — which is a legitimate feature of any democracy — has turned into personal dislike and even enmity.

The death of President Lech Kaczynski in a plane crash in Russia in 2010 deepened the animosity between the two. "You murdered him," Kaczynski told Tusk and PO lawmakers in parliament after the crash.

Kaczynski is convinced that the plane was brought down by a Russian attack and apportions some blame to Tusk, who was prime minister at the time and had traveled alone to Smolensk for the commemoration service marking the 70th anniversary of the massacre of Polish army officers in Russia's Katyn forest.

Kaczynski claimed that this made it possible for Russia to perpetrate an attack on the plane carrying the president and a large delegation from Poland three days later.

There is no evidence to back up this claim; the airplane crashed in dense fog.

Anti-German sentiment

The hostility runs deep. When Tusk sought re-appointment as president of the European Council in 2017, Kaczynski did everything he could to stop him. He did not succeed.

Kaczynski regularly accuses Tusk of representing German — not Polish — interests. He also accuses Germany of harboring bad intentions towards Poland.

But Germany is not the only thing on which the two former prime ministers disagree. While Tusk is an enthusiastic European, Kaczynski is strictly opposed to a strong European Union because he sees Brussels as a tool for German domination of Europe. Instead, he would like to see a "Europe of the fatherlands."

'Retired savior of the nation'

"Jaroslaw (Kaczynski) is only interested in pure power," a PiS lawmaker once told journalist Kamil Dziubka. "He is an emotional psychopath. He pays very little attention to his financial situation. He doesn't give any thought to what he eats for lunch because politics is his food."

Tusk is apparently cut from a very different cloth. Just after Tusk was made prime minister in 2007, journalist Wawrzyniec Smoczynski of the weekly newspaper Polityka referred to him as "Donald Merkel." In doing so, he was highlighting the fact that Tusk was copying German Chancellor Angela Merkel's strategy of small steps and cautious navigation.

Tusk himself described his style of government as a policy of "warm water in the tap" — an approach he defends to this day. The question now, however, is whether that is enough in a Europe that has been fundamentally changed by Russia's attack on Ukraine.

Pivotal election for Poland

This weekend, the two archrivals will once again go head-to-head in a parliamentary election. The stakes are extremely high.

If Tusk loses the election on October 15, it is likely that he will step aside, passing the baton to younger politicians.

Kaczynski's political career could also end if his party loses the election. Whether PiS could continue without him remains to be seen. When asked in 1994 to describe his political ambitions, Kaczynski told a reporter that he would like "to be the retired savior of the nation."

The result of the election may determine whether that day is closer than he thinks.

Adapted from the German by Aingeal Flanagan