A major Democratic group announced Friday it plans to target 17 House Republicans representing solidly red districts, a sign of how Democratic confidence is growing ahead of November’s midterm elections as President Donald Trump’s popularity slumps.

American Bridge, a super PAC focused on generating opposition research, is launching the “Shaky Eights” program — so named because all of the candidates they’re targeting represent seats with a score of at least R+8 in the Cook Partisan Voter Index, a measure of a district’s partisanship. Among their targets are the chair of the National Republican Congressional Committee and a congressman who is set to appear with President Donald Trump in Arizona on Friday.

“As we’ve watched this cycle trend — with the administration’s decisions, the data we’re getting in on economic sentiment, on health care, on all these issues — we basically decided to change our strategy a little bit,” Pat Dennis, the president of American Bridge 21st Century, told HuffPost in an interview. “Basically, our theory of the case is that there are a lot of House seats right now that are not getting enough attention, because they’re considered safe for Republicans. We are putting our chips on the table and saying this is where the frontier of the fight is.”