It was threatening the Russian Federation that caused them to send some military units into Eastern Ukraine, and an expedition down to Kyiv. After a peace treaty was agreed Russia withdrew forces North of Kyiv, but then the US and UK told Zelenskyy where to put the peace treaty and Russian forces remain defending Donetsk and other civilian areas.
We need to ask the question of whether it was threatening the Russian Federation that ultimately caused the war in Ukraine on it's border, or the weapons makers claim that loading Ukraine with weapons would deter Russia.
After 30 years side by side finally there is significant violence in Ukraine. The timing indicates that Biden is somewhere in the equation, but while the media says it was Biden showing weakness, the Kremlin expressed displeasure at the huge army the US and NATO formed in Ukraine, of 680,000 NATO trained and equipped soldiers, about 80% of the size of the entire Russian Army. As Vladimir Putin said 'what is that army for?'. The army and missiles were not necessarily intended to be used, but to frighten the Russian population I would suggest. I'd suggest the neocons started the war not by showing weakness but by threat.
"Russia's total military manpower was estimated at 1,330,900 as of 2023." (Russia military personnel by type 2023 | Statista) There are no NATO troops in Ukraine... " Nato member countries have been providing weaponry and logistical support, but have said they aren't sending troops into Ukraine, which is not a member of the alliance." (War in Ukraine: Fact-checking Russian claims that Nato troops are fighting in Ukraine (bbc.com)) They are, however, lining up on the NATO side of Ukraine's border... just in case. (Bing Videos)