After what the freedom fighters did to Israeli tanks when the Israelis invaded Lebanon the last time, I wouldn't want to send my tanks to Ukraine either. A tank can be taken out completely by a relatively cheap, simple, light, shoulder-launched missile fired by a single ground soldier. The era of tank warfare is as dead as the era of the dreadnauts.

I'm sure there's a few more they can pull out of bogs and swamps in the east.