Bush strong in GOP debate, may be too late

Jeb Bush finally delivered a powerful debate performance. But it may not matter. The son and brother of former presidents repeatedly took the fight to front-runner Donald Trump on Tuesday night as the 2016 Republican presidential candidates met for one of their last debates ahead of the primary season.

Donald Trump and Jeb Bush shake hands after the CNN Republican presidential debate in Las Vegas.

Bush called the billionaire businessman "the chaos candidate", insisted Trump couldn't "insult his way to the presidency" and dismissed Trump's proposal to block all Muslims from entering the country as dangerous and "not serious".

Yet with little more than six weeks before primary voting begins, Bush is struggling for relevancy in a presidential election that has begun to leave him behind. Trump, meanwhile, beat back repeated attacks from his Republican rivals in the primetime face-off to ensure a central role in the 2016 contest, fuelled by deep anti-establishment frustration among the party's angry electorate.

With the Democrats increasingly coalescing behind the candidacy of Hillary Clinton, some Republican leaders worry that Trump's controversial rhetoric will make him all but unelectable if he wins the nomination.
Trump seized on Bush's dismal standing in recent polls and largely shrugged off the criticism.

"I know you're trying to build up your energy, Jeb, but it's not working very well," Trump countered.
"Donald, you're not going to be able to insult your way to the presidency. That's not going to happen," Bush responded.

The exchange was recorded as the "top social moment" of the debate on Facebook, according to the social media organisation. It was the kind of moment Bush supporters had been desperate for in the year's first four primetime debates. That it took several months to materialise highlights Bush's weakness as a candidate, despite having every advantage money could buy. It wasn't supposed to happen this way.