After decades of getting out-organized and outspent in battles to control state legislatures, Democratic strategists have woken up to the importance of defending against Republican gains at the grass roots.

The anger and fear provoked by the advent of President Trump have led to explosive growth for progressive advocacy groups determined to oppose the president’s agenda and, crucially, to elect Democrats to local office — groups like Indivisible, Run for Something, Emerge America and Color of Change (through its PAC).

The number of Democratic candidates filing for office at all levels of government has surged; the trickle of money into liberal grass-roots programs has become a flood; and turnout in post-2016 Democratic primaries has reached record levels.

Until this year, liberals and Democrats have been notoriously neglectful about building local organizations to back candidates for school boards, City Councils and state legislatures. And in fact the differing levels of participation by the right and the left remain striking. The electoral effects have been stark.