The politics of gun control have played a role in decades of presidential elections, but advocates for the movement appear poised to make their greatest gains yet should a Democrat defeat Donald Trump in 2020.

The White House hopefuls are describing recent mass shootings as indicative of an urgent, uniquely American emergency — casting subsequent inaction as among the most glaring moral failings in recent U.S. history.

And national Democrats, united in a visceral opposition toward gun lobbies such as the National Rifle Association, remain galvanized by the wave of activism still emanating from last year’s tragedy at a high school in Parkland, Florida.