Answer:
Would be difficult to gather the will for it among EU members that have strong trading relations with Russia, and even harde.r to enforce. Energy would be off the table; sourcing gas elsewhere may hit the EU harder than Russia. It worked against Iran, but Russia is bigger. Is unlikely to be anything more than a short-term strategy. May kick off a round of ti.t-for-tat reprisals. Would result in the partition of Ukraine by proxy, with the added spice of potential great-power war in the event of accidents. If any forces are deployed, N.AT.O would have to do it, and many members would baulk at that.