Ben Carson
Republican presidential candidate Ben Carson's campaign experienced a staff shakeup during the holidaysGetty Images

Embattled Republican presidential candidate Ben Carson is attempting to move forward after several campaign staffers jumped ship over the holidays. Carson said his campaign is "reinvigorated" following the staff shakeup, which included new leadership positions. The retired neurosurgeon added the his campaign was clearly not working the way it need to before and that it needed a change.

In an interview with CNN's Jake Tapper on 4 January, Carson said that his previous campaign staff lacked "the ability to execute things". He said: "It doesn't mean they're not good people, it means you need to add that in, and that's what the addition was done.

"Some people didn't like that, so they decided they couldn't work with that...I'm very grateful for the contributions they've made."

Last month, Carson's camp announced that five staffers, including campaign manager Barry Bennett, had left. Bennett and Carson's communications director, Dough Watts announced their resignation on 31 December, just weeks before the Iowa caucus on 1 February.

Following his resignation, Bennett placed the blame for the campaign's problems on Carson's close friend and advisor Armstrong Williams. "I called Ben this morning...and explained to him the root of the problem is that you told me Armstrong is not involved in the campaign but he clearly is," Bennett told The Hill. "My frustration level is boiling over so i told him I think it's best that I leave."

Carson replaced the staffers with a new campaign chairman, retired Major General Robert F Dees, and new campaign manager, Ed Brookover. He acknowledged that the staff shakeup announcement was not handled well but added that the changes were "absolutely" needed. "Now we're reinvigorated and I think this is going to be something that everyone's going to notice a very big difference," he said.

New flat tax proposal

As part of his ongoing new campaign, Carson also unveiled a new flat tax proposal on 4 January. The new tax plan would overhaul the current system in favour of a 14.9% flat tax for individuals and corporations alike. Carson's plan, which was revealed during an interview on Fox News, would eliminate tax deductions and loopholes.

"We're looking to provide a ladder to move people upward," Carson said. The presidential candidate said that individuals living below the poverty line would be tax at a lower rate. He did not specify what that lower tax rate would be.

Despite experiencing a high during his campaign, Carson has quickly seen his public support decline. A 23 December CNN/ORC poll showed Carson in third place with Marco Rubio and behind Donald Trump and Ted Cruz.