There is a more mundane reason why sanctions against Russia won't work. There is a global market in Liquefied Natural Gas (LNG), which Russia can trade through neutral third countries (India for example) with the company in that third country taking a cut in the profit. The LNG tanker doesn't even have to go anywhere near that third country. For example, an LNG tanker, under the ownership and flying the flag of the third country leaves a Russian port. Companies in several different European countries bid, without breaking sanctions, for this LNG, which will then end up in one of their ports.
Every country, including those in the EU will want to guarantee its own energy security. As 'Europe', the EU, is not a nation, you can forget about any solidarity when push comes to shove. Russia, by contrast is a nation, whose people are more used to enduring hardship than Europeans are. Sanctions will hurt those companies which rely on exports to Russia, British car manufacturers for example, for whom Russia is an important market, far more than they will hurt Russia.
The USA, if it has a President with any sense, will keep well out of it all and respect the old Cold War practice with Russia of not interfering in each other's sphere of influence.
Every country, including those in the EU will want to guarantee its own energy security. As 'Europe', the EU, is not a nation, you can forget about any solidarity when push comes to shove. Russia, by contrast is a nation, whose people are more used to enduring hardship than Europeans are. Sanctions will hurt those companies which rely on exports to Russia, British car manufacturers for example, for whom Russia is an important market, far more than they will hurt Russia.
The USA, if it has a President with any sense, will keep well out of it all and respect the old Cold War practice with Russia of not interfering in each other's sphere of influence.