I would say, first of all, that Nord Stream 2 was completed. Many people said at the time that its completion would make a larger Russian invasion of Ukraine far more likely, which is what transpired. Weeks after the completion of Nord Stream 2, the full-out invasion was launched. Thankfully, the German government has, for now, cancelled the certification of the pipeline.
Through the last decade or more, a lot of voices in Europe and in North America were making it quite clear to European partners that the policy they were pursuing was not conducive to European security. Nord Stream 2 was strongly opposed by the American government, but it decided to let Germany pursue this policy despite American misgivings. The result is what we see now.
Thankfully, after the full-out Russian invasion of Ukraine, a lot of European countries are revisiting the wisdom of their policy and are changing. It is no comfort to the Ukrainian people or to us that this happened after a Russian invasion in which tens of thousands of people have already been killed and thousands more will be killed.