In Prince William County, where thousands of Hispanics took to the streets four years ago to protest some of the nation’s toughest measures against illegal immigrants, Republican voters will choose next month between two candidates for state Senate — both of them Hispanic Americans.

But the Aug. 23 primary face-off between former Virginia GOP chairman Jeff Frederick, whose mother emigrated from Colombia, and construction company owner Tito Munoz, a Colombian immigrant who became a U.S. citizen three years ago, offers more than just an ironic postscript to the immigration battles of 2007. The race confronts Republican voters with a microcosm of the quandary bedeviling the party nationally: How ideologically pure must GOP politicians be to win the enthusiasm of tea party conservatives, and how far dare candidates lean toward the center to win general elections?

The race in the 36th Senate District, which for the first time this year also includes parts of Fairfax and Stafford counties, at first glance appears to have Frederick in the role of the movement conservative with Munoz playing the more moderate outsider.

In six years as a member of the House of Delegates from Prince William, Frederick was a regular presence at events staged by the Family Foundation, which has won legislative battles to tighten restrictions on abortion, keep same-sex marriage illegal and require the posting of “In God We Trust” in public schools.

Although Munoz includes his firm stance against all abortions in his stump speeches (“I have 250 cousins — does that sound pro-life to you?” he says), he also devotes much of his pitch to the plight of the poor. If elected, he says, his chief goal would be to use state power to create jobs, improve traffic and foster development along Route 1.

“The insiders don’t know what it’s like to be poor or struggling,” said Munoz, who left Colombia at 16 and became a U.S. citizen after the Sept. 11, 2001, terrorist attacks. “I don’t know everything about Richmond, but I have common sense, and I know there are a lot of immigrants who are struggling to make it.”

But the two men vying for a shot at longtime incumbent Toddy Puller (D) do not fit neatly into boxes labeled “tea party conservative” and “moderate.”

Munoz, 50, never thought of becoming a politician until 2008, when then-vice presidential candidate Sarah Palin plucked him out of a crowd at a rally and dubbed him “Tito the Builder,” a Virginia version of “Joe the Plumber,” the Ohio man who became the rhetorical everyman of her campaign. Now, Munoz is being touted as a promising leader by Ginni Thomas, wife of Supreme Court Justice Clarence Thomas; winning support from former senator George Allen; and being described by conservative media firebrand Andrew Breitbart as “one of the greatest voices in the tea party.”

As the accolades indicate, the race defies stereotypes: It is Munoz — the political neophyte who admits he’s still boning up on just what the state legislature does — who is running with support from Virginia and national Republican leaders.

That leaves Frederick, 35, who has not held public office since his short and troubled reign as state party chairman, positioning himself as the outsider, the renegade who promises to stand tall against those who would compromise their conservative principles.

“It’s a tough race for both of them,” said Tom Whitmore, vice chairman of the Prince William County Republican Committee. “Jeff is going to have to renew some old relationships and repair some damage, but he still has grass-roots support from people who see him as a champion for the social issues. Tito is a champion to people who came here for freedom, but he’s new to all this, and he’s a new citizen.”

Although both men tout tea party-friendly positions on shrinking government and rolling back taxes, Frederick now avoids mention of social issues.

“The pro-life people want freedom fighters, but my agenda is let’s shrink government and create jobs,” Frederick said between houses as he knocked on Republican voters’ doors on a 104-degree afternoon in the Lorton section of Fairfax. “The life issue is important to me, but it’s not everything I am.

“I try to focus on issues that impact your daily life. Now, you can argue that killing babies has an impact on daily life, but that’s not what you’re thinking about when you’re driving down the highway in heavy traffic,” he said. “If conservatives are going to govern, we have to have a coalition.”

The notion of Frederick adopting the mantle of realist is startling to some Republicans. Frederick was infamous in Richmond as a dynamic legislator who took pride in resisting compromise and making flamboyantly headline-grabbing statements, such as when he said that Barack Obama and Osama bin Laden “both have friends that bombed the Pentagon.”

Even now, he says he’d rather be known as an uncompromising conservative than as a Republican. “Both parties have trouble with intellectual honesty, and they are filled with people who choose power — real or perceived — over principle,” he told the Virginia Gentleman blog.

But as much as Frederick is known as a tough-talking idealist, his soft voice and slight figure can seem pale compared with Munoz, who grabs audiences’ attention with his barrel-chested presence, his booming, heavily accented voice and his frank admission that he’s learning as he goes. “This is the first debate of my life,” he told a forum in Woodbridge last week.

Munoz’s speeches are much more emotional than Frederick’s, especially when he talks about why he opposes illegal immigration, spinning a long tale about the time when, as a boy in Colombia, he spent all night waiting outside a soccer stadium to get the best seats in the cheap section, only to find that people with connections had been allowed to jump the line.

“I felt cheated, I felt robbed, I felt violated,” Munoz said. “Now you tell me somebody else, somebody who jumped the line, is going to take my place in America? Somebody who doesn’t deserve the opportunity? Not possible.”

At backyard barbecues, tea party enthusiasts embrace Munoz as a model of the entrepreneurial, legal immigrant who eschews government aid. But as Frederick knocks on doors, some other voters hear Munoz’s Hispanic name and tell Frederick, “That’s all I need to hear.”

“Tito is who he is,” said Tim Murtaugh, a longtime political aide to top Virginia Republicans who is working for Munoz. “He’s the embodiment of the American dream. Jeff is a failed politician who ran the state party into the ground.”

Frederick, who notes that he never lost an election and boasts that he “wasn’t in Richmond to make any friends,” is under no illusions about the antagonism many Republican leaders feel toward him. He expects a tough campaign from the same people who ousted him as chairman in 2009, accusing him of mismanaging the party and steering it too sharply to the right, focusing too heavily on gun rights, immigration and abortion.

So far, however, those opponents are not putting their money behind their anger. Frederick has raised nearly five times as much money as the newcomer, according to the latest finance reports.

Munoz and Frederick have appeared together at only a couple of forums but are already sniping at each other. Munoz rolls his eyes at Frederick’s identification as a Hispanic: “If you are born here in the United States and have never lived in another country, how do you know what it is to be Hispanic?” Munoz said.

Frederick says Munoz is simply not ready for the Senate. “At a minimum, people seeking public office should know the responsibilities of the office they seek,” he said. “Tito says this race is about America. No, it’s not. It’s about the people of the 36th District.”

Those people, like voters throughout Virginia, have a long history of staying home for summer primaries. Whoever can turn out his supporters in August will face a tough battle in November. The GOP didn’t even field a candidate against Puller four years ago; before that, she handily defeated Republican opponents.

Even some voters who disagree with Puller like her as a person. “I don’t think she’s done any harm,” said George Verzagt, 77, an insurance agent, when Frederick knocked on his door to ask for support.

“Well, she does think that anything wrong with Virginia can be cured with higher taxes,” Frederick offered.

Verzagt was not swayed. “Well, I don’t really pay taxes,” he replied. “I make very little. I’m very happy with the services here in Fairfax County.”