Confidently isn't the term I'd use for their assault right now. Long distance bombardment of cities, like they did to Grozny, isn't confidence or military brilliant, but it is a meatgrinder that will eventually work.
But mostly, having started it
*, for whatever reasons and probably partially due to believing that he would only get token sanctions, he would look horribly weak to be backing off. Weak personally, and also putting the lie to Russia's great power. A great power that he personally attributes to himself to sell his policies to Russians.
For a democratic leader, backing off from an already started war of choice would be ignominious and eventually send them to retirement at the next election. For a dictator it brings real risk of losing power violently.
It's certainly why the world should not hold too immediate expectations for him to be reasonable now that he has started. He will not be defeated short term on the battlefield and he has nukes to keep the West out of acting directly.
This is also why any reasonable face-saving move to get him out should not be passed over in favor of "taking him out". And also why the, ethically justified and PR-savvy move of accusing him of war crimes should be quietly ditched if he agrees to back out.
* This isn't about why he started - @o.m. makes some very credible points, but surely he can't have expected that Ukrainians wouldn't need a draining long term force to keep them under his boot? Without massive economic support, like Belarus requires? And that NATO, having resisted the much stronger Warsaw Pact, would give in to his demands to cut loose the Baltics and existing Eastern European members? In short restoring the Soviet Union's near abroad by force was a delusional goal that he somehow went for. We don't know why he's acting this way (@Fizz shared this link before).
Not genius, that's for sure, notwithstanding his fan club (woe, to see a day I'd quote Bolton).
BTW, sanctions can work, given (lots of) time:
- South Africa dropped Apartheid
- Myanmar's junta liberalized, even if it reverted later
- Khaddafi abandoned his nuclear bomb plans
These are all considerably less powerful countries and it still took decades. But South Africa is illustrative. Unlike the other two its wider elite was relatively affluent and aspired to a Western lifestyle. Sanctions against a very poor country don't generate the massive transition in circumstances that ordinary Russians are going through right now, from losing their iPhones to not being able to holiday abroad to suddenly becoming pariahs from a world they aspired to mingle with.
Compared to those 3 examples, Russia has also been comprehensively whacked with multiple sanctions from a very wide array of actors in an historically unprecedented short span of time.
And, please, let's not bring Yemen into this. No one's proposing to starve people in Russia and the Yemen sanctions were brought in by a regime who believes in chopping people up in its embassies.