After being demilitarized in 2005, Sweden re-introduced permanent troops to Gotland in 2016, following Russia’s annexation of Ukraine’s Crimean Peninsula in 2014. Sweden also became NATO’s newest member in March — meaning it is covered by the alliance’s Article 5 guarantee that all other members come to each other’s defense if they are attacked.
Then why is Putin considering this? Perhaps he’s the one who played too much C&C. This would definitively end Russia’s imperial ambitions, which is why I think it wouldn’t be a bad thing, on balance.
ETA: it would also be better for Russia to try this nonsense while they’re still embroiled in Ukraine. Giving them time to regroup would only draw this out and make the outcome worse.