Tradition dictates, though, that party organizations generally stay out of picking candidates in primaries, but Moser's profile has the DCCC anxious that it will blow a chance to win a congressional seat from Republican John Culberson.
He warned Republicans that if they stayed at home they would risk losing both the House of Representatives and the Senate to Democrats next fall.
"We are seeing some extraordinary turnout in the Democratic primary in Texas that has us feeling very hopeful about what the general election might look like", Wendy Davis, the 2014 Democratic nominee for governor, told MSNBC. "They are seeing a very energized Democratic base and they're seeing a Republican base that at this point doesn't appear to be matching Democratic enthusiasm or anywhere close to it previous year".
"They are mobilizing in a powerful way", warned Cruz after the polls closed in an interview with the CBS affiliate in Dallas. "Which of the two are going to have a better idea of what's going on in Texas?" The Democratic vote was up in the 15 most populous counties, but the rural vote is still overwhelmingly Republican.
In an unexpected move, Cruz chose to attack O'Rourke by name before the polls had even closed. "We're still going to see a more Republican, conservative, ideological mindset".
The reasoning went that an unpopular president was propelling Democratic turnout to record numbers - and that could portend a "blue wave" in Texas and elsewhere. His policies pushed to the polls Democrats who oppose him and Republicans who support him, analysts said.
"If I owned Texas and hell", Sheridan said, "I'd rent out Texas and live in hell". "And, in that sense, it's becoming a little bit more like California every year".
Culberson's district is a key target for national Democrats trying to win back the U.S. House in November.
Moser's efforts to run an anti-establishment, liberal campaign were somewhat successful, as her second-place finish qualifies her for the runoff election in May.
The Pennsylvania district has more registered Democrats than Republicans, but for years its residents have elected GOP candidates.
In fact, despite longstanding expectations of Texas becoming a so-called purple state, Democrats have not won a statewide office there since 1994.
Statewide, it appears incumbent Agriculture Commissioner Sid Miller has avoided a runoff, incumbent Land Commissioner George P. Bush has a commanding lead over Jerry Patterson, and incumbent Railroad Commissioner Christi Craddick has triple the votes of incumbent Weston Martinez, according to early voting totals from the Texas Secretary of State.
For the most contested House primary races, Tuesday's contests provided no resolution, only a narrowing of the field.
Sen. Ted Cruz has already posted to Facebook following the news of Congressman Beto O'Rourke winning the Democratic nomination. "We saw Hillary Clinton in 2016 lose by single digits".
Bliss said the race should be a warning to Republicans ahead of 2018, with Democratic voters fired up and ready for battle. "They're filled with rage; they hate the president". "And I share some of those frustrations".
Several well-funded Democratic candidates were ousted by competitors who raised far less. She will face leading candidate Lizzie Pannill Fletcher, an attorney, in the runoff on May 22.
GOP operatives have gleefully watched the drama unfold. Things were looking quite robust for the Democrats. As of Wednesday morning, retired Air Force intelligence officer Gina Ortiz Jones led the race with 40 percent of the vote.
If no candidate in a primary receives at least 50 percent of the votes plus at least one additional vote, the top two vote-getters go head-to-head in a runoff election. But regardless of who wins the Democratic primary on Tuesday, both candidates in that race will largely agree on the issue of an expansive border wall when it comes time for the general election. All of the EMILY's List-endorsed candidates in Democratic primaries either won or advanced to a runoff.
"It's rivaling a presidential year, which is unprecedented", he said.