Why didn’t Obama tell everyone about the Russians before the election?

It’s become clear recently that the FBI was investigating both Hillary Clinton’s emails and Russian attempts to interfere with the US election.

Comey has faced criticism – why did he come out about additional Hillary emails ten days before the election, but didn’t mention the Russian interference?

Surely Obama would have been briefed about this.

Why didn’t Obama hold a press conference and tell everyone what was going on?

Is it really that the extent of it hasn’t come to light until recently?

It feels like the Obama establishment really fucked up on this one – instead of fighting like the Russians are – by exposing information, they’re opted for a strategy of secrecy. Hardly does wonders for their credibility.