George W Bush in Donald Trump takedown in support of brother Jeb

George W Bush never mentioned Donald Trump. But, with his folksy touch, the former US president unleashed a tough takedown of the billionaire businessman who has upended a Republican Party his family has long led.

“I understand Americans are angry and frustrated,” George Bush said during his first campaign rally for his brother, Jeb. “But we do not need somebody in the Oval Office who mirrors and inflames our anger and frustration.”

Mr Trump’s rise has confounded the Bush family and its allies. But despite months of predicting the brash billionaire would fade, it is Jeb Bush whose White House hopes are in peril, particularly if he is unable to pull out a strong showing in Saturday’s South Carolina primary.

The former president emerged from his self-imposed political hibernation to try to give Jeb Bush a boost. He layered each validation of his younger brother with an implicit critique of Trump.

He urged voters to back a candidate who will be “measured and thoughtful” on the world stage, a candidate whose “humility” helps him understand what he does not know, a candidate who can win in November’s general election.

America. pic.twitter.com/TeduJkwQF3

— Jeb Bush (@JebBush) February 16, 2016

“All the sloganeering and all the talk doesn’t matter if we don’t win,” he said. “We need somebody who can take a positive message across the country.”

With his brother as warm-up act, Jeb Bush delivered an impassioned version of his campaign speech, touting his experience as Florida governor and vowing he could put Republicans back in the White House for the first time in eight years.

“I can beat Hillary Clinton,” he said of the Democratic frontrunner. “I can promise you that.”