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The 2018 elections in Texas had a decidedly national flavor, led by the battle for the U.S. Senate between Ted Cruz and Beto O’Rourke. But the 2020 presidential race, which is already underway, has a decidedly Texas tang.

With one of their own in the White House, Texas Republicans are keeping their heads down. But two of the many, many Democrats flirting with the race are from Texas, adding an I-10 primary to the national one.

The presidential race could force Texas Democrats to choose between two of their brightest rising stars, in El Paso’s O’Rourke, 46, and San Antonio’s Julián Castro, 44.

Castro, like O’Rourke, has never won a statewide race in Texas.

He’s never lost one, either.

Unlike O’Rourke, Castro has executive experience. He was San Antonio’s mayor for five years, after serving for four years as a member of its city council. President Obama then selected him as secretary of the U.S. Department of Housing and Urban Development, a post he held until January 2017. He was touted as a vice presidential candidate for Hillary Clinton before she chose U.S. Sen. Tim Kaine of Virginia for that role.

Castro and his twin brother, Joaquin, a congressman from San Antonio, have been the subject of sometimes overheated election speculation in Texas for years. Both have turned back numerous entreaties to run for state office; their names were in the mix as recently as last year, when Democrats were shopping for candidates to challenge Republican Gov. Greg Abbott.

But Julián’s presidential studies were already underway. He had a book in the works; that totem of nearly every presidential campaign is now in print, under the title “An Unlikely Journey: Waking Up from My American Dream.”

And this week, he took another step in the presidential dance, saying — on letterhead that included the words “Julián Castro for President Exploratory Committee” — that he will be announcing his plans next month.

It’s a presidential thing, announcing that you’re exploring and that you’ll announce the result of the exploration on a particular date a month away. As with any dance, there’s a specific rhythm to this.

O'Rourke is cutting a different rug. The recent loser of that race with Cruz said before the elections that he had no plans to seek any other office. He spurned presidential talk. But a couple of weeks after the election, he told an El Paso crowd that he and his wife had “made a decision not to rule anything out.”

It’s like the announcement gambol, but sets up the tension about a future decision a little differently. Both are designed to test the waters and to generate news coverage.

Like Castro, O'Rourke has city council experience, but stayed on the legislative side of things, winning a spot in Congress, where he’s finishing a third term.

They begin as friendlies, denizens of the two biggest Texas cities on Interstate 10, two years apart in age, bearers of the hopes of Democrats in a state where Democrats have been on the endangered species list — at least in statewide races — for a couple of decades. And as subjects of national political talk, they’re upholding a long tradition for Texans from both parties.

It's early and nobody knows which candidates will turn out to be "real" and which ones won't. But this is clear: When America looks for national leaders, it always has Texas on the list of places to shop.

The state just buried the third of its four presidents (if you count Dwight Eisenhower, who was born in Texas). Texas names have been on the candidate lists in most presidential races of the last 60 years: Lyndon Johnson, John Connally, George H.W. Bush, Lloyd Bentsen, Ross Perot, George W. Bush, Ted Cruz, and now these two.

It could even put the state in play in two years. Presidential primaries in Texas usually don’t draw big crowds. They’re bigger than non-presidential primaries, but the national races usually are decided before our primaries roll around. One of two recent exceptions was the Republican primary election in 2016, which occurred before Donald Trump secured the nomination. It drew 2.84 million voters, or about 10 percent of registered voters in Texas. Trump finished second, with 26.8 percent of the vote. Ted Cruz, the Texas candidate on the ballot, got 43.8 percent.

The Democrats pulled the same trick a few years earlier, attracting 2.87 million voters in 2008, or 22.5 percent of the state’s registered voters at the time. Hillary Clinton won that year, with 50.9 percent, over Barack Obama, who got 47.4 percent.

Those are the high points, and maybe a mark to hit if two Texas candidates are on the same party’s ballot by the time the March 2020 primaries roll around.

That’s a long way off, and politics is a hard business. December 2018 could be the start of something big. Or it might turn out, for one or both, to be the best month of the whole cycle.