Talk to Republicans around Washington and battleground states about the midterms and their talking points are all but in chorus: the polls are wrong and undercounting GOP voters.

Talk to Democrats, and it’s giddy optimism mixed with an equal measure of trepidation, but for a whole other reason: all those predictions of a blue wave could give thousands of their voters permission to stay home.

“We’ve all been burned,” says one former staffer on Democratic campaigns.

The polls currently show Democrats may be on the verge of an historic blowout. President Donald Trump has the lowest approval ratings of his two terms in office and threatens to be a drag on most Republicans on the ballot. Democrats are in a strong position to snag a majority in the House and the Senate is still in play, but ideological fractures and a party brand that’s in the gutter stand to undermine their showing.…