Ted Cruz, Beto O'Rourke prepare to sprint to the finish in Texas' marquee race of 2018 With early voting starting Monday, the most-watched midterm campaign in Texas, and perhaps in the nation, will likely end with both candidates throwing punches, experts say.

John C Moritz Austin Bureau USA TODAY NETWORK | Corpus Christi

Show Caption Hide Caption Cruz and O'Rourke: A few things to know about them The candidates for a U.S. Senate seat from Texas are a study in contrast.

AUSTIN — The political drama that started with a little-known upstart from the western-most reaches of Texas challenging one of the most recognizable figures in Washington now heads toward an ending experts say will be as noisy as it is ugly.

"Extreme negativity. Sustained negativity. Both sides calling the other side bad things," is how veteran Texas political operative Bill Miller forecasts the two-week sprint to Election Day between Republican U.S. Sen. Ted Cruz and Democratic Congressman Beto O'Rourke of El Paso.

The comments come as Texas' 12-day early voting period launches Monday, signaling the final sprint in what has become the most expensive, and perhaps most-watched U.S. Senate race of the 2018 midterm elections.

RACE STARTED ON HIGH NOTE

The forecast of nasty finish runs counter to the well-crafted image of an upbeat idealist O'Rourke spent the better part of 18 months honing. He entered the race in March 2017, not to run against Cruz, he said, but to restore a sense of noble purpose to a Washington riven by partisan tribalism.

Cruz, the product of the tea party backlash to Barack Obama's first-term as president, initiated his quest for a second six-year term seeking to soften his image as ambitious firebrand who spent freshman year antagonizing insiders from both parties as he laid the groundwork to seek the presidency.

O'Rourke's freewheeling, shirtsleeve campaign style that includes more than a few casual F-bombs at rallies, spontaneous demonstrations of skateboarding prowess and a seemingly nonstop stream of Facebook Live appearances paid off, literally.

Each campaign finance reporting deadline produced headline after headline of record-breaking donations that were capped off by the unheard-of haul of $38.1 million during the three months leading into October.

The totals dwarfed what otherwise would have been Cruz's own record-breaking $12 million total during that period, fueling Texas Democrats' hopes that party's 20-year losing streak in statewide elections might come to an end this cycle.

But while cash piled up for the Democrat, poll numbers sagged as the incumbent systematically — and without much push back — painted O'Rourke as liberal out of step with ordinary Texans.

He sided with NFL players who kneel during the national anthem rather than with police officers, Cruz said. He put the rights of undocumented immigrants above those of hardworking working American, went another charge.

RAMPING UP THE CONSERVATIVE MESSAGE

Cal Jillson, a political science professor at Southern Methodist University in Dallas, said O'Rourke is also suffering from other Republican candidates ramping up their campaign efforts, including Gov. Greg Abbott and Lt. Gov. Dan Patrick, who are both in less competitive re-election fights than the Senate race.

"It's conservative Republican messaging," Jillson said. "Patrick in particular isn't really talking about himself, he's talking about the importance of Republican leadership in the state. I think that laps over to assist Ted Cruz as well.

Since the start of the campaign, Cruz has lobbed grenade after grenade at O'Rourke in political advertisements and during their first debate, while O'Rourke largely remained sanguine.

"Beto O'Rourke is defining Beto O'Rourke, but only Ted Cruz is defining Ted Cruz," said Democratic strategist Harold Cook, warning that unless O'Rourke could punch back he'd go the way Wendy Davis, Ann Richards and other once-promising Texas Democrats with national followings who flamed out once the votes were counted.

More: Latest polls suggest Beto O'Rourke's high-road approach is a path to defeat

When O'Rourke and Cruz met for their second and final debate last Tuesday in San Antonio, it was clear O'Rourke got the message. He needled Cruz, parroting the "Lyin' Ted" nickname Donald Trump gave him during the run up to the 2016 GOP presidential nomination.

At the same time, O'Rourke suggested Cruz was too timid to stand up to the president on issues dear to Texans like tariffs on agriculture products. And he suggested Cruz's re-election campaign is another warmup for a future presidential run.

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The next day, O'Rourke unveiled three 30-second spots, all targeting Cruz.

"Ted Cruz has voted to take away health care for millions of American families," O'Rourke says in one ad that notes Cruz's role in the 2013 government shutdown over the ill-fated effort to shelve the Affordable Care Act. "He's tried repeatedly to roll back protections for preexisting conditions."

BEING NICE NOT ENOUGH

Expect more like that in the days ahead, Miller said, because both camps can afford to drive their message.

According to the latest filings with the Federal Elections Commission, O'Rourke entered the homestretch with nearly $23 million to spend and Cruz had $12 million. Miller predicted both accounts will be close to zero after the polls close on the night of Nov. 6.

"Frankly, O'Rourke has to go negative," he said. "He's not going to make up ground by being nice."

At post-debate chat on Wednesday with reporters, Cruz said he had expected a more combative foe.

"This morning the O'Rourke campaign unleashed the dogs," Cruz said. "Their pollsters have told them they're in trouble, and so the decision they've made is attack and go ugly and nasty."

But the Cruz camp made the same decision more than a month earlier. In late August, Cruz unveiled an ad attacking O'Rourke on the "take a knee" issue, calling on a Vietnam veteran whose legs were amputated after he had stepped on landmine to castigate the Democrat.

Later, he accused O'Rourke of wanting to undercut the Texas oil and gas industry by backing higher taxes and limiting shale shale fracking.

Meanwhile, the O'Rourke campaign boasts that its fundraising success has allowed it to develop a state-of-the-art ground game to identify and get to the polls as many Democratic votes as possible, including knocking having volunteers "knocking on 102,733 doors and making 102,733 phone calls" in a single weekend.

All campaign, Cruz has warned that Democrats, fueled by their disdain for President Donald Trump, will require minimal motivation to vote this cycle. Republicans, he said, must match that enthusiasm for their side.

To that end, as the first early voters cast ballots on Monday, Trump will headline a "Make America Great Again" rally with Cruz in Houston to rally the state's Republican base.

Desi Canela, a Democratic communications strategist who is not affiliated with the O'Rourke campaign, said she was heartened by O'Rourke's debate performance and by the aggressive ad campaign.

"As much as he wants to stay positive and upbeat, it’s time for the gloves to come off." Canela said. "Good for him."

But that's not enough in the limited time left in the campaign, she added. At 33, Canela is part of an emerging generation of Latino activists who say Democrats must do more than simply place a capital D next to their names to earn the votes of one of the party's core constituencies.

Vulnerability among Hispanic voters surfaced in the March Democratic Primary when he was outpolled in South Texas by Sema Hernandez, little-known and underfunded candidate.

Although she calls O'Rourke "a transformational figure" in Texas politics and applauds his willingness to fight for the rights of immigrants, Canela said she worries he's not fully connecting with the day-to-day concerns of working Hispanic families.

WAKING THE 'SLEEPING GIANT'

In the last weeks of the campaign, Canela said she'd like to see O'Rourke in town hall meetings, TV ads, or both, sitting down at the kitchen table with Latino families and hearing about their struggle to find affordable health care and secure jobs.

"We need to feel like he knows who we are," said Canela, who was still in grade school the last time a Texas Democrat won a statewide election. "A lot of Latinos don't feel they still don't know who he is. You're not going to wake the 'sleeping giant' unless you connect with the 'sleeping giant.'"

As for Cruz's closing strategy, Jillson said he has less worry about.

"I don't think Cruz needs to make any changes and he certainly doesn't think he needs to make any changes," Jillson said. "In both debates he was all about hounding the base and energizing the base at every opportunity."

El Paso Times Austin Bureau reporter Madlin Mekelburg contributed to this report.

John C. Moritz covers Texas government and politics for the USA Today Network in Austin. Contact him at John.Moritz@caller.com and follow him on Twitter @JohnnieMo.