Obama has now called for a retalliation against Russia.
1) This is an unproven theory. While it may be supported by Russia's past involvement with cyber attacks against us, we can't make accusations like this.
2) Hillary Clinton claims that this is the reason for her loss. ACCEPT A LOSS! Hillary was a bad person.
3) Russia is now challenging the US to prove the campaign hacking claims or shut up. This is a very realistic response.
According to Joshua Douglas of CNN, "Russia's role is shocking but there's no evidence the vote was hacked."
Making threats like this is unnecessary... Russia is, ultimately, the more powerful country.