Democrats seek wave to bolster House majority

House Democrats are eyeing big gains in Tuesday's elections, propelled by an enormous fundraising advantage, a host of GOP retirements and an unpopular Republican president whose erratic handling of the coronavirus pandemic has threatened to damage his party down the ballot.

Not too long ago, the notion that Democrats would expand their majority in any significant fashion was virtually unthinkable. In January of 2019, at the start of the cycle, the party's campaign arm was bracing to protect dozens of vulnerable lawmakers in red-leaning regions, 30 of whom represent...