Gerrymandering: GOP Strength Locally, Weakness Nationally
In the process of setting electoral districts, gerrymandering is the process that attempts to establish a political advantage for a particular party or group by manipulating district boundaries to create partisan advantaged districts. In addition to its use achieving desired electoral results for a particular party, gerrymandering may be used to help or hinder a particular demographic, such as a political, ethnic, racial, linguistic, religious, or class group, such as in U.S. federal voting district boundaries that produce a majority of constituents representative of African-American or other racial minorities, known as majority-minority districts. Gerrymandering and off year elections have given the GOP a clear advantage in state houses. I imagine that if we synced gubernatorial elections with presidential elections and had impartial (or even just mechanical) districting, the results would be different.
The Courts
They have released several conservative states from the Justice Department oversight of drawing election districts that dates from the Civil Rights era; however, they did so only because the formulas used to draw the districts were out of date. They left open the door for Congress to act; unfortunately Congress didn’t for it’s purposes.
States are still subject to Congressional oversight should racial disparity exists. Again, the Supreme Court did not overturn the ability of Congress to authorize a federal examination of districting based on racial disparities. They merely knocked down the law because it used old data to decide which districts to examine. There was some hope that Congress would reimplement the part of the Civil Rights Act struck down, but the GOP had no interest in doing so.
The GOP
The party is fighting against a demographic shift. They ran a strong state-based campaign in the last decade to keep local support which is eroding. This is seen in national Presidential Elections which have given democrats a tremendous advantage over the last 25-30 years.
I imagine after the 2020 census, when the lines are redrawn, the matter will change in favor of the Democrats unless the GOP by its own admission changes its rhetoric if not its positions. Now both parties gerrymander, but by virtue of their state-directed focus of the ’00s, the GOP was in a position to take advantage more so than the Democratic Party.