The Democratic Congressional Campaign Committee (DCCC) on Tuesday released its "retirements to watch list" of potential GOP targets ahead of the 2020 election cycle.

The House Democrats' campaign arm is releasing customized digital ads for each of the 19 Republican incumbents' districts - many of which saw tough reelection contests during 2018.

The list of lawmakers includes GOP Reps. Don Young (R-Alaska), David Schweikert (Ariz.), Duncan Hunter (Calif.), Ross Spano (Fla.), Vern Buchanan (Fla.), Rob Woodall (Ga.) - who already announced he plans to retire next cycle - Susan Brooks (Ind.), Fred Upton (Mich.), Ann Wagner (Mo.), Chris Smith (N.J.), Pete King (N.Y.), John Katko (N.Y.), Chris Collins (N.Y.), Steve Chabot (Ohio), Michael McCaul (Texas), Pete Olson (Texas), Kenny Marchant (Texas), John Carter (Texas) and Jaime Herrera Beutler (Wash.).

The DCCC noted that retirements played a key role in Democrats winning back the House majority during last year's midterms, adding that just six of the 16 members placed on last cycle's list remain in their positions.

"Whether it's waking up each morning to read the President's tweets that they'll be answering for or slowly coming to the realization that they aren't in control any more, we expect to see a steady stream of frustrated Washington Republicans heading for the exits," DCCC Communications Director Jared Smith said in a statement.

"Retirements played a major role as Democrats won back the House last year and, in 2020, we expect Republican retirements to aid our effort to expand the Democratic House Majority."