Analysis: The 2020 election’s most important Texas race

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It was easy to miss, during the Beto tsunami of the last week, that one of the rising Democratic stars of the Texas congressional delegation has all but decided to challenge U.S. Sen. John Cornyn, who will be seeking a fourth term in 2020.

U.S. Rep. Joaquin Castro, D-San Antonio, was the House author of the resolution to erase President Donald Trump’s executive order to build a border wall (a measure that led to Trump’s first veto). He’s the twin brother of Julián Castro, the former San Antonio mayor and Housing and Urban Development secretary who is now running for president. He’s a former Texas legislator. And he has the same hometown as Cornyn, which could add a little something extra to the Senate race.

That city has plenty of voters and donors who have, at one time or another, supported both Cornyn and at least one of the Castro twins. The parlor games would be fun.

But there’s more at play here than local discomfort. A competitive Senate race in Texas during a presidential election year would attract interest beyond the state’s borders.

Political folk in both parties are still autopsying the 2018 election in Texas, trying to figure out whether that was the beginning of something new or just a political hiccup. Millions more people voted than expected. The Republicans who’ve been dominant in Texas for more than two decades — particularly in non-presidential election years — found themselves in genuine competition.

Ted Cruz remained in the Senate after finishing 2.6 percentage points ahead of Beto O’Rourke. Lt. Gov. Dan Patrick won by fewer than 5 percentage points. Attorney General Ken Paxton won by 3.6 percentage points.

For years, higher turnout in statewide Texas elections has made for closer — though still Republican — races. It’s reasonable to expect high turnout in 2020 since it’s a presidential election year.

And Cornyn’s troops have to be looking at those numbers — and other, deeper ones — as unwelcome tremors in the body politic. Democrats find the numbers comforting, and for the same reasons.

The trends in Texas have drawn enough national attention that, as The Texas Tribune’s Abby Livingston has reported, the Democratic Congressional Campaign Committee has six of the state’s Republican-held congressional seats on its target list.

Strong Democratic performances in either or both of the top two races — president and Senate — will improve their chances.

Before O’Rourke decided to run for president, some were urging him to run against Cornyn. He had the base of support from the Cruz race, a proven ability to raise money, an organization that just finished a statewide race, and all of the qualities that have lots of Democrats and lots of political reporters in full swoon right now.

But the people who voted against Cruz didn’t move to Iowa with the congressman from El Paso. And national Democrats who were hoping the synergy of a competitive Senate race would boost their chances of turning Texas purple might be persuaded that O’Rourke isn’t the only way to make this work.

Neither of the Castro twins — not the one running for president or the one thinking of running for Senate — has ever run for statewide office. They’re both, in a way, in the same place O’Rourke was in before he challenged Cruz: known to voters in one of the state’s big cities and relatively unknown everywhere else in Texas.

And Cornyn isn’t nearly as galvanizing to the opposition as Cruz was, a factor that will make it harder for his challenger — whether that turns out to be Castro or someone else. Democratic voters were excited to come out against Cruz. Cornyn doesn’t yet inspire the same sort of negative enthusiasm.

Texas Democrats put some of their hopes last year in Lupe Valdez, who won four terms as Dallas County sheriff before leaving that job to run for governor against Republican Greg Abbott. The argument was partly about her Hispanic heritage, partly about gender, partly about those four wins in the state’s second-biggest county.

But Valdez was not a great candidate, to put it delicately. Castro could hit some of the same notes that she did — Hispanic, well-known in one of the state’s largest cities — along with some of his own: legislative experience at the state and federal levels, an established political base.

Even holding Cornyn to a narrow win could be beneficial to other Democrats — from the party’s nominee for president to those congressional challengers, and to down-ballot candidates all over Texas.

The race Castro is pondering isn’t just about who the state is electing to the U.S. Senate in 2020. It’s about the whole election.