The math doesn't work out for Russia: Why Putin will never go to war against Europe. Russia's 2024 budget already includes massive investments in military spending.
A doubling of military spending could raise it from six to 12 to 15 percent of GDP - the level that caused the Soviet economy to collapse in the 1980s. A tripling would be even more devastating for the economy. Russia will not be able to recover from this. On the other hand, it is not clear how long Russia can maintain its “war economy”