Ted Cruz appears at a rally at the Shrine auditorium in San Antonio with his wife Heidi and their two children Catherine (held by Ted Cruz) and Caroline (right). (Lucian Perkins/for The Washington Post)

— After a stinging defeat in South Carolina, a drop in national polling and a fade to the background in news cycles, Ted Cruz came home to Texas this week and talked about his many battles.

There was the 2013 fight against an immigration reform bill, which Cruz described in the words of Alamo commander William Barret Travis as a “line in the sand.” There was his crusade to defeat the Affordable Care Act. And now there is Super Tuesday.

The presidential primary here on Tuesday is becoming a pitched battle for Cruz and, like the fight that occurred here in 1836, which Cruz has repeatedly referred to in recent days, it is one that could be his last stand.

Cruz has staked much of his candidacy on winning the large number of southern states that vote Tuesday, including what he calls the “crown jewel,” his home state of Texas.

Nine-year-old Ella Hubert of San Antonio sits with her family and show her support for Ted Cruz at a rally at the Shrine auditorium in San Antonio. (Lucian Perkins/for The Washington Post)

Since its inception, Cruz’s campaign has run a numbers- and data-heavy playbook focused on the delegate game, attempting to amass as many as possible — and the series of 11 primaries and caucuses Tuesday, many in the South, is key.

The campaign has long said the date will be an inflection point that will benefit it: Cruz once called the South a “firewall” filled with religious and conservative voters that could net him a bonanza of delegates and propel him to the nomination.

But now Cruz must grapple with the ascendance of Donald Trump, who has dominated polls across the South and has been sucking up media attention in recent days as he and Sen. Marco Rubio of Florida engage in a dirty battle of insults over spray tans and incontinence. His main ambition now is to win Texas — a goal that has become do or die for his campaign.

Cruz has blitzed across the region, hoping to shore up grass-roots support he has worked to build over the past 11 months and lock down as many delegates as possible to winnow the field to a numeric battle between Cruz and Trump.

The campaign has been battered in recent weeks with accusations that it engaged in unsavory campaign tactics; last week Cruz fired his communications director, Rick Tyler, after Tyler disseminated a video purporting to show Rubio disparaging the Bible. Rubio and Trump have repeatedly branded Cruz a “liar,” an accusation that has stuck with some voters. In the wake of it all, some of Cruz’s most prominent surrogates were publicly calling for the campaign to rethink its strategy and focus on knocking Trump rather than Rubio.

Despite the turmoil, Cruz continues to press on. In recent days he has sharpened his attacks and devoted much of his stump speech to Trump, accusing him of refusing to release his tax returns because of possible ties to organized crime. Here in San Antonio, he called on Trump to release a purported tape of him telling the New York Times off the record that he wouldn’t follow his own rhetoric on immigration if elected president.

The Fix's Aaron Blake sets up the stakes for Republican and Democratic presidential candidates on Super Tuesday. (Peter Stevenson/The Washington Post)

Cruz is also infusing his speeches with populism and painting Trump as dangerous to low-income Americans looking for work, citing reports that Trump hired foreign workers over American ones.

“Let me try a little test here: How many people here have worked as a waiter or waitress?” Cruz asked in Tulsa, as the crowd cheered and many hands shot up. “Take a look at the hands. Donald says you all don’t exist.”

At a rally in Little Rock put on by a super PAC supporting Cruz on Saturday night, the candidate talked about how Trump hired undocumented workers to build Trump Tower.

“He put his name on it,” Cruz said of Trump Tower. “Maybe it should say underneath: ‘built by illegal immigrants.’ ”

Underscoring the weight of Tuesday’s nominating contests, Cruz is telling crowds that Super Tuesday is the most important day of the campaign and that he — winner of the Iowa caucuses — is the only candidate who has beaten and can stop Trump.

“If you don’t want to see Donald Trump as the nominee, if you don’t want to see Hillary Clinton as the next president, then stand with us, tomorrow, on Super Tuesday,” he said to an enthusiastic crowd in San Antonio that chanted, “Cruz! Cruz! Cruz!”

But Cruz also concedes that Trump is the odds-on favorite — something he and his surrogates are calling on voters to halt.

“If he continues with that momentum and powers through and wins everywhere on Super Tuesday, he could easily be unstoppable. And I think that would be a grave mistake both for the Republican Party and for the country,” Cruz told a conference of religious broadcasters in Nashville.

Cruz’s aides say he is sticking to his campaign playbook and is even more focused on racking up delegates, rather than wins, on Tuesday. And the candidate said he believes that the race will come down to him and Trump and that he is not preparing for a contested Republican National Convention in July — a possibility highlighted by Rubio’s campaign.

“I will say a contested convention is the great hope of the Republican establishment. It is how they are drowning away their sorrows,” he said in San Antonio.

The campaign — which once talked of tallying victories across the South — now feels the most confident about notching a win in Cruz’s home state of Texas, where he held rallies in Dallas, San Antonio and his home town of Houston on Monday.

“I think we’re going to have a very good night in the state of Texas,” Cruz said here.

Tuesday morning Cruz sent a message to Rubio, who is trailing Trump in his home state of Florida. “But there is no doubt that any candidate who cannot win his home state has real problems,” Cruz said.

Texas is a delegate bonanza — 155 are available, apportioned to winners of congressional districts — and Cruz is expecting to vacuum up quite a few. He also benefits from the fact that Texans have been voting early.

“Ted Cruz has already won” in Texas, said Steve Munisteri, the former head of the Texas Republican party. But he said Cruz needs to do more than that.

“The odds are if the only state he wins is Texas, I think he will begin a death spiral,” Munisteri said.

Kerwin Swint, a professor of political science at Kennesaw State University in Georgia, said Cruz’s strategy is a good one — but the Trump phenomenon has caused everything to go haywire.

“Cruz’s strategy was sound for what they thought the race was going to look like and almost nobody saw the rise of Trump as being anything significant,” Swint said. “It’s shaken everything, it’s turned it all upside down.”

Nonetheless, Cruz is planning for what he believes will be a victory rally at a place named the Redneck Country Club Tuesday night.

“Tomorrow, Super Tuesday, is, I believe, the most important day in this entire primary,” he said.