A big enough Democratic wave could threaten the party’s existing House leadership team while washing away the Republican majority.

Virginia Rep. Gerry Connolly, a member of Congress since 2009, hears echoes of the post-Watertage Democratic gains in 1974 in this year’s election. Once a defender of House Minority Leader Nancy Pelosi, Connolly said the California Democrat’s future atop the caucus “will depend on the size and composition of the freshman class.”