On September 13, U.S. Energy Secretary Rick Perry threatened to impose sanctions on our ally over the construction of an underwater natural-gas pipeline between Russia and Germany, known as Nord Stream 2.

The Kremlin said the move was economically motivated and an attempt to promote U.S. liquefied natural gas in Europe.

Six days later President Trump ruled out sanctions over the Nord Stream 2 pipeline.

Poland as well as Ukraine, which may suffer a dip in transit revenues if Nord Stream 2 becomes operational, also strongly opposed the venture, while it’s being welcomed by some other countries in Europe, such as Germany and Austria.

What changed in those six days? Germany essentially bribed Washington by giving American companies more access to the European market.

Germany will choose where to build a liquefied natural gas (LNG) terminal by the end of 2018 as a gesture to the United States, which wants to ship more gas to Europe, the Bundesrepublik’s economy minister said on Tuesday (18 September).

In a bid to deter US President Donald Trump from imposing hefty new trade tariffs on European Union goods, the EU said in July it would work to increase imports of US soybeans and LNG.
Trump wants US LNG to compete with Russian natural gas exports in Europe.

Hurray for the free market...?
It's ridiculous. There is no possible way that LNG shipped across the Atlantic can compete economically with Russian gas coming through that pipeline.
This looks more like how the British and French empires treated their colonies in the 18th Century.

Today we are treated to yet another example of American economic imperialism.

The Trump administration imposed sanctions on the Chinese military on Thursday for buying fighter jets and missile systems from Russia, in breach of a sweeping U.S. sanctions law punishing Moscow for meddling in the 2016 U.S. election.

China is royally pissed about these sanctions, and has called on the US to “correct the mistake” or “bear responsibility for the consequences”. But Russia was not surprised by the news.

Kremlin spokesman Dmitry Peskov said on Friday that by imposing sanctions on buyers of Russian weapons, and on people associated with the Russian military, the United States is trying to squeeze out competitors in the global arms trade.

Yes, that is exactly what we intend to do.
Washington is threatening to sanction India and Turkey in an effort to squeeze Russia's market share in the global arms trade.

Our economic imperialism isn't limited to just sanctions on Russia. You can see it in the sanctions on Iran as well.

Falling Iranian oil exports from U.S. sanctions open the door for U.S. oil and gas producers to fill a void in Asia for a niche oil market.

Texas shale is beginning to produce more ultra-light condensate oil and there’s growing demand in Asia, said Sandy Fielden, director of oil and products research at Morningstar, in a new report this week. Iran has served as a major source for condensate in Asia.
...
“Regardless of how much Iranian condensate remains available for export, the current tight conditions represent an opportunity for U.S. producers to gain valuable market share,” Fielden argued.
“Time is of the essence for U.S. producers to grab this opportunity,” he said, “since several competing suppliers are knocking at the same door,” he added.

Yes, it is an "opportunity for market share", isn't it.
You'd almost be tempted to believe that our foreign policy is being shaped by tens of millions of dollars in campaign donations from the fossil fuels and weapons manufacturing industries.
Or was it about a non-existent nuclear weapons program and twitter bots?

Which theory makes more sense in the real world?