Democrats believe Republicans will not be able to shrink the House battlefield: Democratic groups have taken an aggressive approach to the map, probing Republican vulnerability even in districts that tilt to the right. The Democratic Congressional Campaign Committee recently began advertising in six conservative-leaning seats, from rural Pennsylvania to the suburbs of Little Rock, Ark., where they see Republicans slipping. On Thursday, the group began spending money against two more targets: Representatives Brian Mast of Florida, whose red-hued district stretches north from Palm Beach, and Mia Love of Utah, in the Salt Lake City suburbs.
Representative Ben Ray Luján of New Mexico, who chairs the Democratic committee, said the landscape of competitive races was already too broad for Republicans to build an electoral firewall around a chosen few.
“Many of these districts are closing our way,” Mr. Luján said, adding: “There are many paths for us to get to a majority.”
Mr. Luján wryly pointed to Mr. Sessions, 63, as an example of Republican distress, noting that the Republican candidate had suggested last year he would not need help from the national party. Now, Mr. Luján said, Mr. Sessions is “calling the cavalry home to see if they can defend that seat” against Colin Allred, his Democratic challenger.
The Dallas race reflects the territory where Republicans plan to stand and fight. It is a diverse district, about half white, and a highly educated one, with more than two-fifths of residents holding college degrees. Though it has long tilted toward Republicans, voters favored Hillary Clinton over President Trump in 2016, and Mr. Trump remains unpopular according to polling conducted by both parties. The streets are dotted with “Beto for Senate” signs, and Republicans expect Senator Ted Cruz’s Democratic challenger, Beto O’Rourke, to carry the area.
But this is by no means a left-leaning district: many moderates here tend to be registered Republicans, and Democrats have struggled in the past to mobilize its sizable Latino, black and Asian-American communities in congressional elections.