For now the measure remains off the list of sanctions outlined by the West. Why the reluctance?

There are three reasons. Start with the impact on Russia. The Kremlin has been bracing itself for the possibility of being cut off from SWIFT since 2014, when America floated the idea as punishment for the invasion of Crimea. [...] And transactions would migrate en masse to SPFS, a Russian alternative to SWIFT that is not nearly as ubiquitous and sophisticated, but still usable. That would cause some disruption—but not disaster.

Second, the West, and European countries in particular, would face short-term costs. [...] Russia is the EU’s fifth-largest trading partner. It is the source of 35% of Europe’s gas supply and it is home to €310bn ($350bn) of EU assets. Cutting Russia off from SWIFT could make it harder for international buyers to pay for its energy supplies; it could also prompt Russian retaliation.

Last, using SWIFT as a weapon against Russia could hurt long-term American interests. America holds sway over international finance thanks to the dollar’s dominance and its pre-eminent role in global settlement systems. Further politicising SWIFT would give China an incentive to bolster CIPS, its rival to SWIFT for cross-border payments in yuan. It would also help China court any country with uneasy relations with America looking for alternatives.