I agree with you that both parties engage in gerrymandering. However, my understanding is that Republicans have been significantly more successful over the past decade with their gerrymandering efforts. There was a coordinated effort by Republicans to accomplish this with the 2010 Census.
It was never a secret. In 2010, the conservative political strategist Karl Rove took to the Wall Street Journal and laid out a plan to win majorities in state legislatures across the country.
"He who controls redistricting can control Congress," read the subhead to Rove's column.
The plan, which its architects dubbed REDMAP for Redistricting Majority Project, hinged on the fact that states redraw their electoral maps every 10 years according to new Census data. REDMAP targeted states where just a few statehouse seats could shift the balance to Republican control in the crucial Census year of 2010.
That plan worked spectacularly. It's why today Republicans have a majority in nearly two-thirds of the country's state legislative chambers. And it's why in 2012 Democratic statehouse candidates won 51 percent of the vote in Pennsylvania, which voted for Barack Obama in the presidential election, yet those candidates ended up with only 28 percent of the seats in the legislature.
It’s also relevant, IMO, that Republicans have been the most vocal in preventing efforts to end gerrymandering. And that the courts recent rejections of gerrymandering efforts, including North Carolina’s redistricting, have all been on Republican attempts.
I spoke to a Democratic Party legislator in my home state a few years ago and she freely admitted that both sides engaged in this behavior and she was trying to get passed legislation to have the redistricting determined by a map districting expert (I forget the title she used, but it was something different from cartographer). The map drawn would then be reviewed and approved by a panel of judges.
Unfortunately, it’s part of a larger problem with undemocratic efforts to deny representation in the United States. In other countries there is weekend voting so that more working adults can vote. As a result of the US’s failure to allow multiple days of voting, upper income voters and retirees, who skew more conservative, have an oversized advantage in getting their votes in. In person early voting, even when it’s legal, can be relegated to one or two out of the way locations that are not easily accessible by bus, which reduces the number of working poor who can take advantage of in person early voting. Lastly, these locations in my state are only open between 8am and 3pm, meaning you would have to take off work.
There is also efforts to reduce the number of polling locations to the advantage of one party or one candidate over another: on Tuesday there were three hour long lines on college campuses and inner cities. Are you realistically going to wait that long? Many voters chose to leave without voting at those locations. I don’t remember any news reports of three hour long lines in the suburbs or at nursing homes, which skew moderate to conservative.