Trump needs to tell Sessions to tell Mueller to put up or get fired. Either he has credible evidence on Russian interference or you are fired. This cannot be a deep sea fishing expedition on the people’s dime by a corrupt hack and Hillary supporters.
In 2018 the Dems have a lot of jeopardy in the Senate where a lot of their operatives are up for reelection. Far more than on our side.
It's a different story in the House.
Should things go wrong and the press get traction immediately before the election we could lose a few in the House and not gain as many as we should in the Senate.
However, it pays to remember that the dems have isolated half of their constituency by the way they savaged Bernie Sanders in the last election.Also the DNC is broke and being sued for far more than they will take in for years.
The DNC would be gone dead and buried if it were not for the driveby media which now is effectively the Democrat party.
It is up to Rosenstein to keep Mueller within the rails. According to Rosenstein this morning, Mueller is supposed to ask for approval if he wants to widen the investigation. He used Ken Starr's investigation of Clinton as the example. Starr asked permission to widen the investigation.