I suspect that these Republican 'cowards' will run for re-election in two years and most of them will be re-elected, whether they choose to be ambushed by violent folks in their Districts or not.  

The Democrats in the House of Representatives numbered 257 to Republicans 178 when Obama took office in 2008.

Today, the Democrats in Congress number 194 to Republicans 241 .

This is a net loss by the Democrats of  63 seats. 

A 'normal' off year election results in the President's party losing seats in the House. 

 Trump didn't bring any House members in on his coattails and I don't believe his presence will make that kind of difference in two years.

Most of the 'establishment' Republicans (including the Speaker of the House) threw him under the bus this year and somehow Trump still got elected.  

I expect those Representatives to make it on their own and actually benefit from the nasty publicity being generated by the current groups of low-life scum who see violence as the solution.