Putin beordrar styrkor att gå in i Ukraina - INVASION NU (2022-02-24)

The best comparison is the battles of World War II, which showed that offensives against well-prepared defending forces often start out messily with heavy losses even when ultimately successful.

After the bloody D-Day landings in Normandy, for example, Allied forces spent several weeks advancing slowly at great cost. Finally, the British attempted a massive tank assault to punch through German defenses only to lose hundreds of tanks in rapid succession. But a week later, American forces succeeded wildly, as the Germans had used most of their reserves containing the British.

https://edition.cnn.com/2023/06/16/opinions/ukraine-russia-military-counteroffensive-biden-roblin/index.html

Recall that Ukraine began its Kherson counteroffensive late in August but only forced Russia to retreat in November. This campaign is likely to last roughly that long. And the current, even more difficult and costly attempted breach of Russian fortifications, requires superb coordination of armor, infantry, air defense, artillery and engineers to pull off.