In South Texas, Democratic Rep. Henry Cuellar is facing a fierce challenge from Jessica Cisneros, a 26-year-old immigration attorney who has become a cause célèbre on the left and boasts endorsements from Sen. Bernie Sanders (I-Vt.) and Rep. Alexandria Ocasio-Cortez (D-N.Y.). A national network of progressive donors have given her solid funding, but Cuellar — one of the most conservative members of the Democratic conference — insists that her support for "Medicare for All" and the "Green New Deal" don’t play well in the district.

Meanwhile, in California’s Central Valley, Blue Dog Democratic Rep. Jim Costa is facing a liberal opponent in Fresno City Councilwoman Esmeralda Soria. Only one of them is likely to advance from the top-two primary with a Republican, but Costa is the favorite after outspending her by more than 4-1.

In north Texas, Rep. Kay Granger, one of just 11 Republican women left in the House, is facing a stiff challenge from technology executive Chris Putnam. Backed by the conservative Club for Growth, he’s hitting Granger as a big-spending appropriator who is running up the deficit. But Granger has establishment backing and the all-important Twitter endorsement from President Trump. This race could be a test of whether small-government attacks still animate Republican voters in the Trump era.

Can a Bush win in a GOP primary in the Trump era?

The GOP primary in Texas’s 22nd congressional district in the southern suburbs of Houston offers a unique political science experiment. Pierce Bush, the grandson of George H.W. Bush and nephew of George W. Bush, is testing the appetite for compassionate conservatism in Trump’s GOP.

Party recruiters feel Bush, a nonprofit leader, would be a top-tier general election candidate in a district that has become an emerging battleground in recent years, in part because of his family name and his unique connection to the many minority communities in the district. But first he has to get through a 15-candidate primary — in which his top opponents are questioning his loyalty to Trump.

Elsewhere in Texas, a slew of Democrats, including 2014 gubernatorial nominee Wendy Davis, are vying to win the nominations in a half dozen GOP-held seats that came close to flipping in the midterms. Republicans will nominate challengers to freshman Democratic Reps. Lizzie Fletcher and Colin Allred. Expect many of these races to head toward a May 26 runoff.

The California-25 special election

Tuesday’s special election will whittle down the list of contenders vying for former Democratic Rep. Katie Hill’s northern Los Angeles district. House Democrats feel confident their preferred candidate, state Assemblywoman Christy Smith, will advance to a runoff on May 12 and have been spending to try to pick her opponent.

Private polling from both parties indicates a two-way race for the second spot between Navy veteran Mike Garcia and former Rep. Steve Knight, who lost to Hill by 8 points in 2018. The DCCC hopes to face Knight, who has had abysmal fundraising and is likely wounded after a bruising midterm, so they have dropped nearly $500,000 in ads to kneecap Garcia. Liberal radio host Cenk Uygur is running, as is former Trump adviser George Papadopoulos — but neither is expected either to advance.

The former members making a comeback

Two former Republican congressmen drummed out during the 2018 midterms, Pete Sessions and Darrell Issa, are attempting 2020 comeback bids. But in a sign of just how quickly the suburbs have trended away from the GOP, they have both decided to run in new districts.

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Issa, who retired last year from a seat Democrats ultimately flipped by 13 points, is vying for a top-two finish in the race for a district vacated by embattled GOP Rep. Duncan Hunter. Radio host Carl DeMaio and 2018 Democratic nominee Ammar Campa-Najjar are Issa’s main competition.

Even though the 50th is California’s most Trump-friendly district, Campa-Najjar is likely to finish in the top two, with Issa and DeMaio competing for GOP votes.

Over in Texas, Sessions moved 100 miles south from the suburban Dallas district he handily lost in 2018 to run for a deep-red, open seat based in Waco. That district’s incumbent, retiring Republican Rep. Bill Flores, has spurned a run by his former colleague. Sessions has a shot at earning a runoff berth. He’s been slow to fundraise this cycle but had $380,000 leftover in the bank from the 2018 midterms to apply to his campaign this year.