The top diplomats from both countries want to limit Russian gas — in part because it gives Moscow political influence. But energy sales also drive the economy, which helps the Kremlin finance foreign military ventures.
Secretary of State Rex Tillerson expressed the US's support for Poland's position after meeting his counterpart, Foreign Minister Jacek Czaputowicz, in Warsaw.
"Like Poland, the United States opposes the Nord Stream 2 pipeline," Tillerson said during a news conference with Czaputowicz. "We see it as undermining Europe's overall energy security and stability and providing Russia yet another tool to politicize energy as a political tool."
Baltic states oppose Nord Stream 2 pipeline
Tillerson added: "Our opposition is driven by our mutual strategic interests."
The undersea pipeline would be the second to deliver Russian gas directly to Western Europe via the Baltic Sea, bypassing the traditional land route through Ukraine and Poland.
"We share the view that it is necessary to diversify energy supplies into Europe," Czaputowicz said.
Russia still provides two-thirds of Poland's gas supply, but Warsaw started importing liquefied natural gas from the United States last year in its own bid to diversify its fuel supplies.
Closer military ties
Tillerson encouraged other European countries to follow suit and also voiced support for a pipeline connecting Poland and Norway, which Warsaw is developing with the aim of further limiting its dependency on Russia.
Poland, which spent four decades under Soviet rule, has been an EU member since 2004. Many officials consider Russia an existential threat, particularly after Moscow seized the Crimean Peninsula from neighboring Ukraine in 2014.
Poland's northern neighbors — Lithuania, Latvia and Estonia — are also alarmed by Moscow's aggression and Europe's dependency on Russian energy supplies. But Germany and Austria have focused on the commercial benefits of importing cheap gas from Russia.
Separately, Tillerson and Czaputowicz pledged to enhance military cooperation, including increasing the US's military presence — which currently numbers 5,000 across two separate missions related directly to the US and to NATO — in Poland.
"The stationing of American troops on our territory gives us, the Poles, a sense of security, and we are grateful for that," Czaputowicz said. "We want this presence to be even bigger, and we want it to be permanent."