That's literally how we got here. Russia has been appeasing NATO as it deploys nuclear capabilities on it's border in many countries. This most recent move by NATO, under US direction, to establish nuclear capabilities on the Ukraine border could no longer be managed through appeasement and diplomacy. It's not like Russia hasn't tried, it's not like the US didn't know Ukraine was a red line for Russian national security. Russia has been appeasing US nuclear expansion for decades, and slowly demonstrating their willingness to fight back. Now they're in a proxy conflict where the US is pumping Ukraine full of the equipment Ukraine needs to send out soldiers. If the US hadn't done that, Ukraine would have far more people still alive and would have capitulated far earlier and begun negotiations. This is the same pattern we see every time the US pumps up a proxy, the proxy suffers the most.