The 13 additions bring the number of Red to Blue races to 51, a number that DCCC Chairman Rep. Steve Israel (D-N.Y.) says indicates how far ahead of the game Democrats are in their effort to take back the House this fall. Israel said the expanding number of competitive races also reveals how harmful the 2010 Tea Party wave was to Republicans.

“It’s clear that the tea party wave that swept all these Republicans into office in 2010 is going to cost Republicans seats in 2012,” he said.

The Red to Blue designation offers candidates greater access to DCCC resources, including technical support and validation to national donors.

The new additions are as follows:

Julia BrownleyJulia Andrews BrownleyPelosi heading to Madrid for UN climate change convention A dozen House Democrats call on EU ambassador to resign amid Ukraine scandal Katherine Clark quietly eyes leadership ascent MORE (Calif.-26)
Alan Lowenthal (Calif.-47)
Scott Peters (Calif.-52)
Bill Enyart (Ill.-12)
David Gill (Ill.-13)
Mike Obermueller (Minn.-02)
Hayden Rogers (N.C.-11)
Michelle Lujan Grisham (N.M.-01)
Carol Shea-Porter (N.H.-01)
Mark Murphy (N.Y.-11)
Sean Patrick Maloney (N.Y.-18)
Pete GallegoPete Pena GallegoGOP candidate scores upset win in Texas state Senate runoff Koch group launches digital ads in tight Texas House race Iraq War vet wins Texas Dem runoff MORE (Texas-23)
Suzan DelBeneSuzan Kay DelBeneCongressional authority in a time of Trump executive overreach Moderate Democratic lawmakers back privacy bill favored by businesses The Hill's Morning Report - Presented by National Association of Manufacturers - Trump, Congress draw battle lines on impeachment MORE (Wash.-01)

DelBene is an unsurprising addition to the list, as she was considered the best possible candidate to challenge Tea Party-affiliated candidate John Koster. After winning her primary on Tuesday night, she’ll likely see growing support from the party apparatus to ensure a win there.

Notably missing from the list, however, is Democratic candidate Syed Taj, running against newly minted Republican opponent Kerry BentivolioKerry BentivolioIndiana Republican: Leaders duped me Reindeer farmer saves 'cromnibus' with yes vote High drama as .1T spending package advances by one vote MORE for Thad McCotter’s old seat, in Michigan’s 11th district. Bentivolio’s Tea Party credentials concern Michigan Republicans, as Obama managed to win 50 percent of the vote there in 2008, indicating it could be competitive this year. But DCCC spokesman Jesse Ferguson said that they’re still watching the district to see how the race will develop in the coming weeks.

“The Republican failure to get a credible nominee has made it an opportunity. We're assessing it and continue to add races to the Red to Blue program in the weeks ahead,” he said.

The DCCC noted four races as “emerging races,” districts that political observers should begin to pay closer attention to as things there “ripen,” Israel said. Those include Arizona’s 1st district, where Democrat Scott Ellington faces Rep. Rick CrawfordRichard (Rick) CrawfordThis week: House kicks off public phase of impeachment inquiry House Republicans add Jordan to Intel panel for impeachment probe Republican Congressman: DNI Nominee committed to declassification transparency MORE (R); Minnesota’s 6th district, where Democrat Jim Graves faces incumbent Rep. Michele BachmannMichele Marie BachmannMellman: The 'lane theory' is the wrong lane to be in White House backs Stephen Miller amid white nationalist allegations Klobuchar urges CNN town hall audience: 'That's when you guys are supposed to cheer, OK?' MORE (R); Democrat Kim Gillan running in Montana’s at-large district; and Michigan’s 3rd district, where Democrat Steve Pestka is running against Rep. Justin AmashJustin AmashGroup of Democrats floating censure of Trump instead of impeachment: report Democrats gear up for high-stakes Judiciary hearing Here are the Senate Republicans who could vote to convict Trump MORE.

The last race is somewhat surprising, in that it was left off the Red to Blue listing — Pestka’s win there on Tuesday night excited Dems hopeful for a win against incumbent Amash. Israel said that while Democrats were “presented with some good opportunities” from Tuesday night’s primary, the DCCC is not yet willing to commit resources to any races there.

“We’re going to make those decisions in a real-time basis,” he said. “That’s dependent on the situation on the ground.”