>but was rational back then.
Only if you're a corrupt German politician getting bribed by Russia to sell out long term national security for short term corporate profits.
It was also considered a stupid idea back then by NATO powers asking Germany WTF are you doing, tying your economy to the nation we're preparing to go to war with.
> The idea was to give russia leverage on europe besides war, so that they don't need war.
The present day proves it was a stupid idea.
"You were given the choice between war and dishonor. You chose dishonor, and you will have war." - Churchill
Here’s a nice history of the decades old relationship: https://www.dw.com/en/russian-gas-in-germany-a-complicated-5...
It was a major success, contributing to the thawing of relationships with the Soviet Union and probably contributed to the peaceful end of the Soviet Union. It supported several EU countries through their economic development and kept the EU afloat through the financial crisis.
It was a very important source of energy and there is no replacement. This can be seen by the flight of capital, deindustrialisation and poor economic prospects in Germany and the EU.
But as far as I know, many countries still import energy from Russia, either directly or laundered through third parties.
It worked quite well between France and Germany 50 years earlier.
Yes it was naive, given the philosophy of the leaders of the UdSSR/Russia, but I don't think it was that much problematic. We do need some years to adapt, but it doesn't meaningfully impact the ability to send weapons to the ukraine and impose sanctions (in the long term). Meanwhile we got cheap gas for some decades and Russia got some other trade partners beside China. Would we better of if we didn't use the oil in the first place? Then Russia would have bounded earlier only to China and Nordkorea, etc. . It also did have less environmental impact then shipping the oil from the US.