When does peaceful protest become a crime? How much disruption can a society handle? Do the rights of peaceful demonstrators outweigh the needs of ambulances, fire engines or commuters?
Those are the questions being fiercely debated in Germany on Thursday morning, after the homes of Last Generation environmental activists were raided by police early Wednesday.
Last Generation's spokeswoman said about 25 police officers carrying guns stormed her bedroom while she was in bed, breaking down the door of her apartment in the Berlin district of Kreuzberg.
"We don't know what they were looking for," said one activist, "we only have glue and high-vis jackets."
Conservative politicians and many newspaper commentators on Thursday morning applauded the raids.
The Cologne daily, the Kölner Stadt-Anzeiger, called Last Generation's actions "blackmail" and said the activists should win people over, rather than punish them for the government's mistakes.
Left-wing politicians and voters accuse the police of being heavy-handed. They say an organisation with the same aims as the government cannot be called criminal.
"Why are cannons being used to shoot sparrows?" asks the Reutlinger General-Anzeiger.
The same issues are being discussed in the UK. But the environmentalists disrupting transport to highlight the climate emergency are part of a different group; Just Stop Oil.
The tactics of both groups are similar.
Last Generation activists glue themselves to roads or vehicles to block traffic as a way of highlighting climate change.
Over the past month, German activists have focused on Berlin: on Tuesday, at least five separate roads were blocked, as well as the main motorway around the city - twice.
Both organisations also stage high-profile stunts involving artwork: Just Stop Oil protesters have thrown soup at Van Gogh's Sunflowers, while Last Generation activists threw mashed potatoes at a Monet painting.
But their concrete demands are different.
Just Stop Oil's targets are big-picture, including an end to fossil fuels and more renewable energy. Last Generation has specific aims which, compared to their radical actions, seem modest and technocratic: a 100 km/h speed limit on motorways; a €9 (£7.80) public transport monthly ticket; a citizens' council to plan how to scrap fossil fuels by 2030.
Activists say they are offering concrete suggestions and want to talk to political leaders. In some German cities, mayors negotiate with Last Generation activists in return for an end to protests.
But the big difference between the two countries is the legal and political environment.
Germany's 20th-Century experience of Nazi and communist dictatorship means that the right to protest is sacrosanct.
In the UK, two Just Stop Oil activists were jailed for up to three years for scaling the Dartford Crossing bridge and unfurling a banner, which then led to traffic delays.
The British government's new Public Order Act gives police more powers to crack down on climate protests, with heavier penalties and actions that would not legally be possible in Germany.
In Germany, activists who block roads typically receive fines. But in March, for the first time, Last Generation activists were handed a prison sentence which was not suspended.
Two men received sentences of a few months for repeatedly glueing themselves to roads and blocking traffic. The sentence sparked outrage among civil rights campaigners. Wednesday's police raids have made the debate even more ferocious.
Videos on social media regularly show angry drivers shouting at and sometimes attacking activists. It might seem surprising that the discussion over climate is so fierce in Germany.
After all, this is a country with the Green Party in government, with effective recycling, widespread bike use and heavily subsidised public transport. The government not only has ambitious legally binding climate targets, but also, unlike the UK, concrete policies to reach them.
But Germany is also a country with a powerful auto industry, where the car is often king. Debates over pedestrianising roads turn into tortuous political battles lasting years.
The recent Berlin regional election was partly fought between a conservative campaign for more rights for drivers and Green demands for better bike paths. The conservatives won.
Rows regularly blow up between two of the parties in Germany's three-way governing coalition: the Greens and the liberal pro-car pro-business FDP, which views driving a Porsche without a speed limit on the motorway as a fundamental liberal right.
Both parties are struggling in the polls, making them even more desperate to fight for their ideological values. Social Democrat Chancellor Olaf Scholz's contribution to the debate this week was to describe the actions of Last Generation as "completely crazy".
The car is at the heart of Germany's culture wars. The popular tabloid cliché is sausage-eating, car-driving German traditionalists, being bossed around by moralistic young vegans.
Mainstream Germany is, as ever, more nuanced. But the extremes appear to be getting more radical. No wonder blocking a road can get heated.