Sweeping Midterm Gains in House May Be Challenge for Republicans

Overshadowed by their party's battle for control of the Senate, House Republicans are setting their own ambitious goal for the midterm elections: Expanding their majority to near a post-World War II high.

It won't take much to get there: House Republicans say they hope to pick up 11 seats, which would bring them to a 245-190 majority—strength the GOP hasn't seen since 1947, when it had 246 House seats.

But hitting that target might prove difficult. A gerrymandered political map has left few incumbents of either party vulnerable to serious...