 Republican presidential candidate Donald Trump speaks during a campaign rally at Jacksonville Veterans Memorial Arena, Wednesday, Aug. 3, 2016, in Jacksonville, Fla. (AP Photo/Evan Vucci) (Associated Press) 
 
 DAYTONA BEACH, Fla. (AP) — Republicans' frustration with Donald Trump has reached new heights, with party leaders scrambling to persuade their presidential nominee to abandon divisive tactics that have triggered sinking poll numbers and low morale. But the idea that the campaign was fully united was undercut when Mike Pence, Trump’s vice-presidential running mate, told Fox News Channel that he “strongly endorsed” Ryan in his primary campaign.  The Republican National Committee is categorically denying reports that party officials are looking into how to replace Donald Trump Donald John TrumpEx-White House counsel interviewed Whitaker about joining Trump's legal team: report Flake slams Trump for doubting Arizona vote count: No evidence of 'electoral corruption' Comey talked about sensitive FBI matters on personal email: report MORE in case he drops out of the presidential race before Election Day. | Getty Trump: ‘I don’t know why we’re not leading by a lot’ 
 
 Donald Trump said he’s puzzled as to why he’s not leading Hillary Clinton by large margins at a rally Wednesday night, making no mention of the controversies that have mired his campaign all week.
– Donald Trump is the GOP nominee for president and there will be no refunds or exchanges, the Republican National Committee insisted Wednesday amid rumors that Trump's missteps had panicked it so badly it was looking at options for a replacement and planning to pressure him to drop out. "Donald Trump is the nominee of the Republican Party full-stop," RNC strategist Sean Spicer tells the Hill. "That's the reality. The rest is just a media-pundit concoction." A roundup of coverage: Despite talk of internal turmoil—and his running mate's endorsement of Paul Ryan—Trump told a rally in Daytona Beach, Fla., Wednesday that the campaign is "doing really well" and has "never been so well united," the BBC reports. CNN reports that for the first 11 minutes of the Daytona Beach rally, Trump stayed on-message in a way that would have pleased top GOP officials, slamming Hillary Clinton and President Obama over a $400 million payment to Iran. The next 40 minutes, however, were a more familiar mix of attacks on a wide variety of targets, including Megyn Kelly. But despite the public talk of unity, sources tell the Washington Post that RNC chief Reince Priebus is "disturbed" and "frustrated" by Trump's recent behavior, particularly the feud with the Khan family, and is seeking a campaign reboot. The Trump campaign has firmly denied rumors that Priebus and Trump allies, including Newt Gingrich, are planning an "intervention" to get him back on track. Sources tell the AP that Priebus is so concerned by the way Trump is splitting the party that he's trying to enlist Trump's children to help. At a second Florida rally on Wednesday, Trump boasted about huge turnout at his rallies and told the Jacksonville crowd he doubted Clinton could get a crowd of 500, Politico reports. "I hear we're leading Florida by a bit," he said. "I don't know why we're not leading by a lot. Maybe crowds don't make the difference." According to a Fox News poll released Wednesday, Clinton is up 5 points from a month ago and now leads Trump by 10 points nationwide, 49% to 39%. Some 61% of voters consider her untrustworthy, while 62% feel the same way about Trump.