(CBS News) With control of the Senate up for grabs this November, all eyes have turned to a handful of high-profile contests viewed as critical for both major parties in their respective quests to either acquire, or hold on to, the Senate majority. But in Texas, a primary runoff between two Republican candidates also threatens to have broad implications for the upcoming elections - and, if some conservatives have their way, the future of the Republican party at large.
On Tuesday, Republican Ted Cruz - a Tea Party favorite who has never been elected to public office - will face off against the state's Lieutenant Governor, David Dewhurst, in a runoff for the nomination.
In the months ahead of the race, Dewhurst, a longtime fixture of the Texas' Republican establishment, was widely expected to clinch the nomination with relative ease. But in May's primary,after a - and pledged that in the July 31 runoff, he'd be the candidate with an advantage.
As Texas Republicans head to the polls today, it seems that Cruz may be right.
Despite a lack of reliable polling in the race, all signs suggest that Cruz, a Cuban-American lawyer, has gained significant traction against his opponent since the May 29 primary.
"Ted is gaining momentum around Texas," said James Berensen, a spokesperson for Cruz. "People are really hungering for a strong conservative fighter who won't just go to Washington to vote on bills, but to actually be a leader. People across Texas have recognized that Ted will be that kind of leader. That's really fueled a lot of momentum and enthusiasm in this race."
The candidate has recently attracted the support of Sarah Palin, who last week traveled to Texas to campaign for the candidate, as well as of Jim DeMint, Rick Santorum, and Rand Paul. He's been touted as a rising Tea Party star and, in the words of conservative writer George Will, is a candidate who's "as good as it gets." Dewhurst, on the other hand, boasts the support of Governor Rick Perry, a popular political figure in Texas.
Even if Cruz does not win, as many are predicting he will, a close second place finish for the candidate could still count as a victory for conservatives, according to James Henson, who directs the Texas Politics project and co-directed a University of Texas/Texas Tribune poll on the race from May.
"Clearly Cruz has made significant inroads," Henson said. "Unless Dewhurst wins by 10 or 15 points on Tuesday - which I think is unlikely - this race has exposed some pretty significant differences in approach, if not ideology, within the Republican Party in Texas. And I think you could probably extend that to the national level to some degree as well."
As elsewhere in the country, where a handful of longtime Republican incumbents and establishment picks - namely, Indiana Senator Richard Lugar and Nebraska Attorney General Jon Bruning - were upended in the 2012 primary process by upstart Tea Party candidates or virtual unknowns, Henson argues that now is just not a good time to be an establishment candidate. (Longtime Sen. Orrin Hatch, R-Utah, on the other hand, survived a Tea Party primary challenge in part by pumping up his conservative credentials.)
"This is the second straight election cycle in which we've seen the argument that familiarity with government and experience in the process is seen as a negative rather than a positive," Henson said. "The grassroots in the Republican party have internalized the skepticism of government that Republican candidates have been trading n for the last decade. And incumbents are now suffering from the blowback of that. I think that's very much what we're seeing here."
Whereas many viewed Lugar and Brunings' defeats as isolated incidences, a Dewhurst loss could be read as a broader shift among Republican voters toward Tea Party and conservative candidates - and could lend credibility to the groups pushing those candidates to run.
Unlike Lugar, long famous for his moderate Republican politics, Dewhurst is perceived by many Texas political insiders as substantively conservative. And while Lugar was criticized for running a lackluster campaign, Dewhurst has spent considerable time and money - including upwards of $20 million of his personal fortune - in an effort to win this race.
"There's very little political policy and ideological difference between Ted Cruz and David Dewhurst as senators in motion," says Henson. "But the heart of the Cruz critique of Dewhurst is that he was not conservative enough and that he was a compromiser as someone who worked in government. The notion of compromise and moderation has negative value in a Republican primary right now - particularly in Texas."
Enormous quantities of money have been spent on behalf of both candidates, including millions in contributions from super PACs and bundlers. The Republican Club for Growth, a super PAC that advocates a conservative vision of limited government and often supports Tea Party candidates, has alone contributed $5.5 million toward getting Cruz elected, it says. It also invested heavily in the campaign for Richard Mourdock, the Tea Party candidate who beat Lugar in Indiana earlier this year.
According to Corbin Casteel, a Texas GOP strategist, a Cruz victory would enable Tea Party leaders and outside groups like the Club for Growth to tout a new strategic success - and to warn "all incumbents and establishment Republicans: 'You're on notice.'"