COLUMBIA, South Carolina — Republican presidential front-runner Donald Trump is boasting about keeping his lead in the polls, but that isn't deterring him from sniping at rivals and complaining about the media. Eclipsed this week by Pope Francis' tour of the US, the billionaire developer and former TV reality show star spent Wednesday slinging insults. He said in a question-and-answer session with reporters that Sen. Rand Paul was not adequately representing his constituents in Kentucky because he spends so much time campaigning for president. “I think they're being taken advantage of by Rand Paul,” he said. “You should either run for the Senate or run for president.” Trump also took a jab at Marco Rubio, calling the Florida senator a “lightweight” for criticizing him on his lack of foreign policy experience. “He sits in the Senate, and I'm out creating jobs,” Trump said. Earlier, at a session in North Charleston, Trump said Rubio and former Florida Gov. Jeb Bush “hate each other, but they can't say it.” “I'm so tired of this politically correct crap,” he said. He tweeted Wednesday that he's boycotting Fox News, even though the network said officials there had canceled a Trump appearance first. Trump has been feuding with Fox since the first Republican primary debate, when he objected to moderator Megyn Kelly pressing him to explain insulting comments he's made about women. One woman who has been the target of Trump insults is former Hewlett-Packard executive Carly Fiorina. Trump suggested that Fiorina, who is surging, might be broke. And Democratic front-runner Hillary Rodham Clinton is “shrill,” he said at another, adding that her campaign “is coming down like a really, really sick rocket.” At the North Charleston event, Trump cast Fiorina — another “outsider” candidate trying to appeal to anti-establishment Republicans — as another politician looking for donors who will ultimately control her. “Carly is out there fighting to raise money,” he said. “She doesn't want to spend her own money. Maybe she doesn't have it.” Fiorina suggested Tuesday in a stop at Myrtle Beach, South Carolina, that she is making Trump “nervous.” Trump repeated his assertion Wednesday that Clinton, during the 2008 presidential campaign, started the discredited “birther” movement whose members falsely claim that President Barack Obama was not born in the United States. There's been no evidence tracing the charge to Clinton or her campaign. In an interview on The Tom Joyner Radio Show earlier Wednesday, Clinton called Trump's assertion that she started the birther claims “ludicrous.” She told guest host Don Lemon: “You know, I have been blamed for nearly everything. That was a new one to me.” At an event in Columbia, Trump denied opponents' comments that he had been a Barack Obama supporter. “I helped John McCain. He did a bad job. He didn't get elected,” Trump said, adding later that he felt “even Abraham Lincoln” couldn't have won against Barack Obama in 2008. “I helped Romney, he didn't get elected. I said, ‘This time I'm going to do it myself, OK?'” — AP