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How in the world did U.S. Sen. Ted Cruz — Republican of Texas, former presidential candidate, Texas solicitor general, U.S. Supreme Court clerk, double Ivy League graduate — get positioned as the underdog in his first race for reelection?

Not that he’s really the underdog in this campaign against U.S. Rep. Beto O’Rourke, D-El Paso. It’s still a Republican state. O’Rourke has been through more elections as a candidate than Cruz, but none on a statewide level. The financial advantage belongs to the challenger, but only if you don’t count the outside political committees and groups that financed Cruz in 2012 and that are jumping to his defense now. And the polls, close as some of them are, consistently have found that the incumbent has the advantage.

For all that, the challenger plays as the juggernaut in the race — to the point where the glowing profiles of the Democrat have spawned parodies. Even people in his own party are fretting. Mick Mulvaney, a former member of Congress who’s now the federal budget director, was recorded telling a private Republican group that Cruz might be in trouble. “There’s a very real possibility we will win a race for Senate in Florida and lose a race in Texas for Senate, O.K.?” Mulvaney said, according to The New York Times. “I don’t think it’s likely, but it’s a possibility. How likable is a candidate? That still counts.”

Nothing beats friends in high places.

Mulvaney, awkward as he might have been, was only echoing others and Cruz himself. Lt. Gov. Dan Patrick — one of the downballot Republican candidates with a close personal interest in a healthy Cruz performance at the top of the ticket — appealed to the White House to send President Trump to Texas to stump for Cruz, according to Politico. Cruz, meanwhile, has been imploring lackadaisical Republicans to match the apparent Democratic enthusiasm by turning out to support him. The other side, he said recently in Houston, “is angry, is unified and is trying to burn down the White House.”

Again, the odds are in the incumbent’s favor. Still, the spin on this race is that the leader is somehow in a defensive posture. For reporters and pundits and other storytellers, it’s a narrative roller coaster. A political newcomer wins his very first race — for U.S. Senate, no less — against a very wealthy Texas lieutenant governor who had won four statewide elections in a row. He’s a rambunctious conservative, disruptive in a way that delighted his voters and irked the stuffy U.S. Senate. He runs for president in a packed GOP field, losing to the only candidate in the race more subversive than he.

It’s fair to say Ted Cruz made an impression along the way. It’s fair to say, too, that Beto O’Rourke’s crescendo is based on the same desire for something new that boosted Cruz six years ago, along with Democratic antipathy to the GOP majority in general and to the junior senator in particular.

But O’Rourke has to manage one of three difficult pathways to victory: turn out a lot of Texans who don’t ordinarily vote, benefit from a lot of Republican voters being discouraged and staying home, or convince a sizable number of Republican voters to also vote for the Democrat at the top of the ticket.

So far, that’s been a better political tale than the expected one — where an incumbent seeks another six years and sails to victory.

The sprint to the elections is another chapter. Cruz and groups that support him have launched a commercial siege on the challenger — an attempt to introduce him in the worst possible light to an electorate that is already familiar with Cruz and just getting to know O’Rourke. The polling so far — always in Cruz’s favor but not by enough to lower Republicans’ blood pressure — has been of registered voters and not of likely voters. In Texas, fewer than two of every five voters actually turns out.

It'll tighten up. The story line will change, more than once. And even though he’s running a defensive race, a Cruz loss in November would still have to be counted as a seismic upset.