The best example may be Pennsylvania. President Obama won the state by five percentage points in 2012, thanks to a whopping 83 percent of the vote in Philadelphia and Pittsburgh, where Democrats combine nearly unanimous support among nonwhite voters with large margins among young and well-educated liberals. Mr. Romney didn’t win a single Pennsylvania county, let alone a district, by as much as Mr. Obama won Philadelphia and Pittsburgh. The large Democratic margin in these cities allowed Mr. Obama to carry the state, but it did not translate to a majority of House districts.
He didn't include the district map, with those funny shapes around Pittsburgh and Philadelphia:
He also apparently didn't read Sam Wang in the NYT on the same topic.
Third, gerrymandering is a major form of disenfranchisement. In the seven states where Republicans redrew the districts, 16.7 million votes were cast for Republicans and 16.4 million votes were cast for Democrats. This elected 73 Republicans and 34 Democrats. Given the average percentage of the vote it takes to elect representatives elsewhere in the country, that combination would normally require only 14.7 million Democratic votes. Or put another way, 1.7 million votes (16.4 minus 14.7) were effectively packed into Democratic districts and wasted.Of course, Nate's recommendation is to nominate more Blue Dogs....