Rigging the geography of districts does not fully explain the GOP’s grip on the House, but in Michigan, at least, it definitely had an impact:
State House: 1,536,711 (51.2%) total votes cast for state House Democratic candidates that resulted in 47 Democratic House seats (43%)
1,464,983 (48.8%) total votes for state House Republican candidates result in 63 Republican House seats (57%)
State Senate: 1,483,938 (49.3%) total votes for state Senate Democratic candidates result in 11 Democratic Senate seats (29%)
1,528,393 (50.7%) total votes for state Senate Republican candidates result in 27 Republican Senate seats (71%)
U.S. Congress: 1,506,455 (49.1%) total votes for Democratic congressional candidates result in 5 Democratic congressional seats (36%)
1,458,264 (47.6%) total votes for Republican congressional candidates result in 9 Republican congressional seats (64%)
That last one is a little jaw-dropping, innit?