Donald Trump did not dominate the sixth debate among the most prominent Republican candidates for president, but he may have been its prime beneficiary. Trump held his own through an evening of challenges from the FOX Business Network moderators and from six rivals with him on stage. There were plenty of slings and arrows all around, yet Trump did nothing to discourage his fans while watching his main rivals carve each other up. He even had a moment of thoughtful connection while defending his "New York values." Sens. Ted Cruz and Marco Rubio slammed each other's records and impugned each other's integrity for one lengthy segment of the debate's final hour, going mano-a-mano in a blood-letting that may not help either in the long run. The debate lasted nearly 2 1/2 hours, testing the seven men who still have significant standing in national or early-state polls. They were making their last best-televised appeal until they meet in Iowa to debate just days before the caucuses in that state kick off the actual voting season on Feb. 1. Thursday's debate was held in Charleston, S.C., in the state that will hold its own early primary on Feb. 20. The event was held before a large, lively crowd, like most of the other Republican debates, and featured considerable cheering and even catcalls and boos. At first the crowd seemed to be behind Cruz in his duel with Trump, but it later seemed to be with Rubio when he went after Cruz. Cruz was the man on camera most often through the evening. The hardliner from Texas showed a bit of why he has made few friends in the Senate yet become a hero to millions of conservatives. Cruz was on the spot early because Trump has recently questioned whether Cruz's Canadian birth met the "natural born citizen" qualification cited in the Constitution. Relying on his mother's U.S. citizenship, Cruz usually dismisses such questions as a "nonissue" or a matter of "settled law." But in this debate he raised a competing theory instead, saying "the more extreme conspiracy theorists" thought someone had to be born in the U.S. to parents who were also both born in the U.S. (a standard raised by very few and never applied to presidential candidates in the past). Cruz pointed out that neither he, nor rival Marco Rubio, nor even Trump himself could meet that strenuous a test. (Trump's mother was born in Scotland.) But by so doing, Cruz eluded the real question of whether he needed to have been born in the actual United States in order to be legally elected president. And once that issue had been raised by FOX Business Network anchor Maria Bartiromo, Trump was more than willing to respond to Cruz's attempts to sidestep it. "That wouldn't work," he said. "I was born here. Big difference." This was not the only clash between the two men who are leading in Iowa polls as well as in national soundings of the GOP. The moderators also raised Cruz's recent remarks about Trump having "New York values," which had been an applause line for him on the hustings. Cruz spoke of "socially liberal" New York as a city obsessed with "media and money." Trump came back, not with his characteristic aggression or bluster, but with a measured answer about the values by which his native state and city had rebounded from the attacks on Sept. 11, 2001. He said New Yorkers in those days and months earned the admiration of the world. Later, talking to reporters in what is called the "spin room," Trump said, "I guess the bromance is over," a reference to his falling out with Cruz after the two observed an uneasy truce in the earlier debates. Cruz had refused to join other candidates' efforts to take down the national front-runner, and Trump had returned the favor by holding his fire. But as Cruz has moved up, and moved ahead in Iowa, Trump has countered with the questions about Cruz's birthright eligibility. "The Constitution hasn't changed," Cruz quipped. "But the poll numbers have." Rubio, pouncing on Cruz much later in the debate, unleashed a flurry of attacks on a range of issues. Cruz had harkened back to Rubio's 2013 bill overhauling the immigration laws — a bill Cruz has called "amnesty for illegals." Rubio noted several issues on which Cruz had changed his views or his stance, including the availability of green cards and legal status for immigrants in the country illegally, Trade Promotion Authority for President Obama, military spending levels and even the status of whistleblower Edward Snowden. "He called Snowden a public servant," Rubio said. "When I'm president if we can get our hands on him, Snowden will be prosecuted as a traitor." Cruz had a chance to rebut what he called "at least 11 attacks" from Rubio and said at least half of them were "clearly false." But he spent his time primarily on answering the assertion he had favored lower military spending. Also going after Rubio was Chris Christie, governor of New Jersey, who at one point said he was going to answer a given issue because "you had your chance Marco and you blew it." Christie also reprised a popular thrust he had made in earlier debates by referring to the Washington way of debating issues on the floor of the Senate, contrasting it with a governor's obligation to actually govern. Rubio had nettled Christie earlier by referring to issues on which he had supported Obama and for him "sending a check to Planned Parenthood" — the women's health organization that has been a target for the Republican candidates because it provides abortions. Christie flatly denied sending any money to Planned Parenthood, causing Twitter to come alive with reporters and others saying they had proof Christie did so in the 1990s. In response to a question from moderator Neil Cavuto about a 45 percent tariff on Chinese goods entering the U.S., Trump said the quotation was wrong. "It's The New York Times, said Trump, "they are always wrong." Cruz had earlier denounced The Times for its "hit piece" on the loan he received from the investment bank of Goldman Sachs at favorable terms to finance his bid for the U.S. Senate in 2012. Cruz's wife, Heidi, worked for the bank at the time, and he has said they used their own retirement accounts to pay for the campaign. Cruz called it "a paperwork error" that he reported the loan properly in one disclosure form but not another. Jeb Bush, the former governor of Florida, found several opportunities to assert himself, especially on the question of immigration. He went after Trump's proposed exclusion of all Muslims, saying it made it impossible to recruit and retain allies in the international coalition against ISIS. In fact, he said, he made the case ISIS is trying to make against the U.S. Bush had earlier called Trump's suggestion "unhinged," and he stood by that on Thursday night. Less noteworthy than in any debate since the campaign began was Ben Carson, the neurosurgeon who surged to the upper ranks in the polls in the fall. Since the terror attacks in Paris on Nov. 13, however, as the campaign focus shifted to national security, Carson has faded. Recent turmoil in his campaign has included the resignation of his finance director, which was announced the day of the debate. The moderators turned to him last in the questioning sequence and Carson made a joke about needing to be awakened. Also somewhat marginalized was John Kasich who, like Christie, barely made the statistical cut to participate on the main stage. Four others who did not make the cut were invited to an earlier debate in the same location. Three participated: Mike Huckabee, Rick Santorum and Carly Fiorina. A fourth, Rand Paul, declined the invitation. Kasich was given regular questions by the moderators but was not engaged by the other candidates as much as Trump, Cruz, Rubio and Christie. That meant he could not get response time, or get involved in the back-and-forth that animated the evening. He spent his camera time reciting his accomplishments as a member of the House and as governor of Ohio since 2010.