Good question! It would seem that the best way to get an autocratic system to change is to sanction the autocrat himself.
But there is professional courtesy in geopolitics, apparently. Asked this directly, a senior administration official this week said, “It is a highly unusual and rather extraordinary case for the United States to sanction a head of state of another country. So we do not begin these types of sanctions efforts with a head of state.”
It’s also unlikely that Putin has any assets anywhere the US can touch. If the administration feels it needs to ratchet up the pressure, it is far more likely that Mr. Obama will order sanctions on entire sectors of the Russian economy, particularly its oil and natural gas exports.