You're mistaken. Obama retaliated against the Russians just before he left office.

There's been so much controversies and it's been in the news so much that the Democrats and Republicans want to impose additional sanctions. 

The Russians never responded to Obama's sanctions but they are responding Congress' sanctions. 

Congress needs to be accountable for this latest sanctions from Russia. Putin is pretty clear that he's actions are only in response to Congress. *** for tat.