BRUSSELS — President Trump said “it really makes Germany a hostage to Russia.” Senator Ted Cruz, Republican of Texas, said it would encourage Russian “military adventurism.” Radoslaw Sikorski , the former Polish defense minister, compared it to the infamous 1939 Molotov-Ribbentrop Pact that allied the Nazis with Stalin’s Soviet Union.

That seems like a lot of heavy breathing for a pair of natural gas pipelines known as Nord Stream 2 , which follow the route and would double the capacity of an existing pair of pipelines, Nord Stream, which started working in 2011 and are running at full capacity.

The pipelines run from Russia directly under the Baltic Sea to Germany, bypassing Poland and Ukraine and denying those countries some transit fees. Gazprom, which is majority owned by the Russian government, owns 51 percent of Nord Stream 1 and all of Nord Stream 2 AG , which is developing and will operate the new pipelines.

Critics, including those from the United States, which would like to sell Europe more liquefied natural gas , say they are not simply concerned that Germany will become too dependent on Russian gas as it weans itself from nuclear power and coal. They also fear that Russia’s larger intention is to starve Ukraine of an important chunk of income. Russia is waging a kind of war in the eastern part of Ukraine after annexing Crimea in 2014 .