Jan Cienski in Warsaw -

Donald Tusk is suffering through some of the toughest times he has experienced since becoming Poland's prime minister in 2007 - which doesn't mean that there is any viable alternative to the rule of his centrist Civic Platform (PO) party.

Tusk had long been the affable man of Polish politics - shying away from taking on painful economic reforms while quickly swooping in to grab telegenic issues like sending the police out to shut down semi-legal drug shops. But the second wave of the economic crisis has made his second term in office much trickier than his first 2007-11 stint.

Pushed by ratings agencies, Tusk has embarked on a host of needed changes - especially tightening the tax code to end popular loopholes and moving to increase the retirement age to 67 from its current 60 for women and 65 for men. The result has been an outcry, with thousands of workers taking to the streets around parliament, and threats from unions that they may disrupt the European football championships being played in Poland this June. "They're going to work us to death!" said Elzbieta Sienkiewicz, a school teacher taking part in a recent protest in central Warsaw. "I want to retire after working 40 years and see the world, but that's going to be impossible. The government's proposal is just shocking."

Tusk's PO is now sagging in opinion polls, at one point falling below 30% for this first time since 2007, and controversy over the pension changes caused visible tensions in the coalition with the smaller rural Peasant's Party. But in the end, Tusk managed to keep the coalition together and the reforms looked likely to go ahead. "Tusk, PO and this government has always been strong due to the weakness of their opposition and despite the political fracas on pension reform, that hasn't changed," writes Mujtaba Rahman, an analyst with the Eurasia Group, a think-tank. "Although the pension reform debate has been noisy, no credible opposition challenge to Tusk and/or this coalition look likely."

No opposition

The reason that Tusk is managing to soldier on despite polls showing opposition to pension reforms above 90% is the enormous weakness of the conservative opposition Law and Justice party (PiS), which is much less concerned with actuarial tables than with the April 2010 air crash that killed the Polish president, Lech Kaczynski, and many other senior officials. That's because Lech Kaczynski was the twin of opposition leader Jaroslaw Kaczynski, who is still in mourning over his brother's death.

Although official investigations conducted by Polish and Russian authorities placed the bulk of the blame for the crash on the undertrained military pilots, who tried to land the Russian-built Tu-154 airliner in a dense fog at a degraded military airport near the Russian city of Smolensk, Kaczynski is increasingly giving air to the view that his brother's death was no accident. "I have a feeling my brother was murdered," Kaczynski told the Onet internet portal.

Kaczynski's supporters give full-throated approval to that view. A parliamentary commission looking into the crash and filled largely with PiS loyalists is mulling the idea that the plane was brought down by two explosions as it was coming in to land. Other more outlandish theories have posited that the Tu-154 crash-landed in Smolensk, but that the survivors were assassinated by Russians, that the Russians artificially generated the fog, that the airliner's controls were jammed as it tried to land, or that mysterious equipment injected helium into the air, changing its density and causing it to crash.

For Kaczynski's supporters, the idea that an airliner carrying many of the country's most important people - on their way to commemorate the wartime murder of Polish officers by the Soviets in the nearby Katyn forest - ploughed into the ground because of pilot error is impossible to accept. "Look at the whole of Polish history, the Russians have always been trying to destroy us - this is more of the same," said Eryk, a young man in a black leather jacket taking part in a recent PiS rally.

A protest outside the Russian embassy on the eve of the second anniversary of the crash had demonstrators hang Tusk and Russia's President Vladimir Putin in effigy - accusing Tusk and Polish President Bronislaw Komorowski of colluding with Moscow to kill Lech Kaczynski.

It is an open question whether Kaczynski - an intelligent man who served two years as prime minister - really believes that his brother was assassinated. A former close aide interviewed by the Polish edition of Newsweek accuses the PiS leader of being a cynic playing the issue for political gain.

That is Tusk's conclusion as well. "I would rather have never been born than build my political career on the graves of the dead," Tusk thundered in parliament on April 10.

"It is your fault," riposted Kaczynski. "Everything that happened before the catastrophe is your fault... In a political sense you bear 100% of the responsibility for the catastrophe."

The political fireworks have captivated the Polish media - but Kaczynski continues to appeal to only about a quarter of voters and is widely seen as unelectable, as even people dissatisfied with Tusk are unlikely to throw their support to PiS. That leaves Tusk able to push through his economic reform programme despite his party's loss of support.