With two months to go until Election Day, and early voting kicking off later this month in half a dozen states, Democrats are increasingly optimistic they can recapture congressional majorities.With the final stretch towards the midterms underway, Democrats see an unexpectedly favorable political environment despite their own weak national brand, while Republicans insist structural advantages and the Democrats' shift to the left will allow them to defy midterm history.Senate Republicans control their chamber by a 53-47 margin, and the majority is even more fragile in the House. And the latest...