They haven't failed. They need advanced firepower and continued support. Putin from the start is relying on you lot sticking a spoke in the gears, and unsurprisingly conservatives are lining up to do his bidding.
You have a golden opportunity to boost US businesses (most Ukraine aid never leaves the US); hammer a rival, hostile nation; and prevent further encroachment on your allies. Further, all this comes at zero cost of US lives.
Or you could let Putin win.