On Monday, the Supreme Court upheld a district court ruling issued last year that struck down the congressional map that North Carolina Republicans drew in 2011 on the grounds that lawmakers had engaged in unconstitutional racial gerrymandering, handing voting rights advocates a major victory and dealing a huge blow to what was arguably the most effective congressional gerrymander of the modern era. As shown on the map at the top of this post (see here for a larger image), Republican legislators used surgical precision to pack black voters into just two districts, the tentacular 1st and the snake-like 12th.