The ONE thing that could be used across the country is what they just did to themselves. As of 16 January 2018, there were 238 Republicans in the House, and 193 Democrats. Virtually every one of the Democrats (173 of them) co-sponsored the bill, thereby putting 174 Democrat names on it (including the one that introduced it). That could be a great Republican refrain to keep echoing over and over and over between now and November 2020: “A vote for a Democrat is a vote for the vast majority of Democrats that signed their names to ban your guns!”
Added to that, out of the 193 House Democrats, 174 of them should be put on notice that they’re out next time.