Biden is a lame duck president with NO PUBLIC MANDATE and subterranean approval rating, he got ousted by his own party before the election for being mentally incapacitated, his defense against a Justice Department inquiry is he's too old and senile, his party just got BTFO in a national election. No NATO or NATO proxies have ever launched long range missiles into Russia in living memory. How is this guy 
fit for office
STOP EATING CRAYONS AND DO YOUR FUCKING JERB. "Senile old man sends young people to WW3 out of spite"
The game of chicken was inherent since January 2022, arguably even before. Ukraine as a state outside of either regional defense treaty and situated in between both has pointed towards increasing involvement/meddling of the regional powers.
A war being in progress involving a country from one bloc is an opening for the other bloc to conduct indirect opposition. This was known from the start of the SMO, and arguably accounted for from the same time too.
A few missiles hitting a depot in Bryansk is not going to change the course of the war. If it was going to, you'd expect that the USA would have encouraged this to be done sooner. It hasn't broken any continuity woth the rest of the conflict, and isn't going to change much besides maybe a proportionally tiny amount more of destruction on the Russian side of the border. That was my point.
If you don't know the history of this game of chicken, then I don't know why you're in here trying to argue. This game of chicken has been ongoing since shortly after WW2.
After the dismantling of the USSR, this game of chicken is pretty clear cut - the USA has been marching a transnational nuclear military staffed and led by originally by Third Reich officers that has as one of its primary mandates the maintenance of fascist partisan groups throughout Europe to use against any leftist government and also against Russia and Russian regional hegemony.
The game of chicken has always been a proxy conflict and neither side has dared allow an advanced weapon to be used against the other side's sovereign territory.
The use of ATACMS against Russian territory is a net new escalation in this 80-year game of chicken. Will it change the course of the war is not the question. It is an incremental escalation of intent that either is appeased or is rebuffed. And Russia has demonstrated since 2014 that it has abandoned the 100% appeasement strategy.
As we all know, appeasement doesn't really work, so Russia now has a serious problem on their hands with ATACMS landing in their territory. It doesn't need to be tactically transformative for it to be a strategic watershed.