He knows the Republicans will let him do what he wants and the Dems won’t. He doesn’t give a fuck about the Dem party, but by destabilizing them and sowing chaos he will bring about the victory of his preferred team. As you said, that’s all he cares about. (Thought I find no reason to believe he will stop his conquest at the former borders of the USSR. I think he will grab as much territory and power as he is able.)