But this new US plan to not just send more military hardware - but also US military advisers - would mark a serious escalation, as the Kremlin has recently warned it would see any kind of NATO forces buildup inside Ukraine as violating its "red lines" which would require taking action.
Yup. And ratcheting up:
https://www.zerohedge.com/geopolitical/biden-mulls-sending-extra-weapons-trainers-ukraine-amid-dubious-reports-russian
But this new US plan to not just send more military hardware - but also US military advisers - would mark a serious escalation, as the Kremlin has recently warned it would see any kind of NATO forces buildup inside Ukraine as violating its "red lines" which would require taking action.