Newtown — The four Republicans heading toward an Aug. 14 primary showdown struggled Thursday during the one of their final debates to set themselves apart from one another, while still hitting all of the core GOP principles.

For most of the two-hour evening debate at town hall — before an audience of about 200 — Justin Bernier, Mark Greenberg, Lisa Wilson-Foley and Andrew Roraback insisted they were very different from one another while echoing similar positions on taxes, the national debt, the economy, health care reform and gun control.

But when they did find differences, the candidates jumped on them quickly and often.

The four couldn’t find terms glowing enough to capture their feelings about capitalism.

Wilson-Foley, a Simsbury businesswoman who owns a chain of physical therapy clinics, said she rose from humble roots in church-subsidized, low-income housing in Middletown because she learned to appreciate the opportunities that free enterprise offers. “I went from very low income to have control over my destiny,” she said. “That’s what makes American so unique.”

“Free enterprise is not perfect, but it’s certainly better than anything else,” said real estate developer Mark Greenberg of Torrington. “I believe in American exceptionalism.”

Roraback, a state senator from Goshen, was prepared to “sing from the rooftops that capitalism is the best economic system ever devised.”

Similarly, all four pledged to support extension of the federal income tax cuts — for all income groups — enacted a decade ago under President George W. Bush.

“This is not time to increase taxes on anyone,” Wilson-Foley said, adding that the 15 percent tax rate on dividends doesn’t just benefit the wealthy. Many seniors retired on fix incomes rely on dividends from their investments to survive, she said.

“The now dysfunctional Congress” should extend the tax cuts and then “create a new tax code,” streamlining the existing one, Greenberg said.

Bernier, of Plainville, an Afghanistan War veteran who advised Gov. M. Jodi Rell on veterans affairs, pledged not only to support the Bush income tax cuts, but also to fight to reduce corporate levies and to repeal inheritance taxes.

Similarly, the four couldn’t pledge fast enough to support repeal of President Obama’s health care reform initiative.

“We have to make sure that the candidate nominated has been against Obamacare since Day 1,” said Bernier.

Roraback said new burdens on businesses to provide health coverage are destroying business confidence and represent “the biggest impediment to job creation on the map today.”

The Goshen lawmaker, who has served in the state legislature for 18 years, stressed his service in Hartford as a vital feature his GOP competitors could not match.

“I’m the only candidate who’s ever won an election in this district,” he said. “The Republicans can pick up this seat if we run the right candidate.”

But Bernier, who has tried to cast himself as the most conservative candidate in the race, and others argued that Roraback’s track record in Hartford is far more liberal than the senator would admit.

“Andrew, I love you, but for you to call yourself a conservative is just not true,” Bernier said, charging Roraback with supporting state financing for “earmarks,” or pet projects in legislators’ home districts. “You have a liberal record. You ought to just be a man about it, stand up and defend it.”

“Justin, you need to get your eyes checked,” Roraback fired back, adding that he repeatedly has challenged Gov. Dannel P. Malloy, a Democrat, to block state financing for earmarks. “There could not be more daylight between us.”

“We have to stop sending career politicians down (to Washington) whose only goal is to get re-elected,” Wilson-Foley said, adding that Roraback backed a major state fuel tax increase in 2005.

Roraback also took some heat for introducing a bill that would allow resident aliens who are legally in the United States, and who own property, to vote on municipal education budgets in referendums.

“I believe that only U.S. citizens should be allowed to vote in the United States of America,” Bernier said.

“There’s a lot of other states that extend that opportunity” to legal immigrants, Roraback said. “I thought we wanted people more involved in our education system, not less.”

Just a few minutes later, though, Bernier and Roraback teamed up to challenge both Wilson-Foley and Greenberg, two wealthy candidates who have infused their respective campaigns with significant amounts of their own cash.

“We have never elected a congressman, a senator or a governor who were self-funders,” Bernier said, adding that most of the $700,000 he has raised has come from small donors.

Roraback also noted that self-funding, wealthy candidates haven’t fared well lately, adding that he doesn’t need great personal wealth to win in November. “After I win the primary, I will have no difficulty attracting the financial support for my candidacy,” he said.

Wilson-Foley said she has raised about $600,000 from contributors, and roughly matched that with her own money, adding that measures like this are necessary “to make up for all of the unions and all of the organizations that make up the Democratic machine.”

Greenberg, who said he put about $1.1 million of his own money into the campaign to complement $300,000 he has raised, added that the stakes are too high not to make the investment. “I really owe this to the next generation,” he said. “The money is almost worthless if we don’t fix the problem in Washington.”

Wilson-Foley also found herself on the defensive when Roraback asked why she hadn’t disclosed that a federal grand jury is investigating why her husband paid former Gov. John G. Rowland $30,000 as a business consultant to his health-care company while Rowland was advising Wilson-Foley as a volunteer and touting her candidacy on his radio show on WTIC-AM.

Wilson-Foley retorted that federal authorities never contacted her campaign or her business, and that the entire investigation was a “political ploy” to interfere with her candidacy. “I feel very confident,” she said, “that the truth will prevail.”

In addition to the four Republicans vying in the Aug. 14 GOP primary, three Democrats — House Speaker Christopher Donovan, Elizabeth Esty and Dan Roberti — are competing to win their party’s primary the same day.