“Europe can shut them out but then Euope raises its own costs oth financially and diplomatically as I am sure that sort of government action would bring retaliation from this end. “
And the energy giants can retaliate and refuse to provide energy. A cold Europe would be an unhappy Europe.
Someone would figure out a way around any sanctions, just like Marc Rich did after Guiliani got an indictment against him for selling Iranian oil. Rich wound up with enough cash to be an angel donor to the Clinton Personal Enrichment Fund in exchange for a pardon..
Europe would find itself reliant on Russia for energy and the price would, of course rise significantly as it does when you limit the market.