Jeb Bush comes out swinging at Donald Trump in Republican presidential candidate race but it's a risky business

A recent poll shows Trump with 30 per cent of Republican support nationally with Mr Bush on just 8 per cent

Jeb Bush says that every day Donald Trump attacks him ‘with barbarities’ (AFP)

Exactly what pushed Jeb Bush over the edge, we don’t know. Maybe he’d spied the devil letters T-R-U-M-P painted on the roof of the spiffy Doral Country Club as his plane approached Miami Airport a week ago – they are hard to miss – and despaired.

Or did coming home after a long stretch on the road give him new courage? Either way, last week was when he let his new nemesis really have it.

The onslaught against Donald Trump, whose commanding lead in the race for the Republican nomination has stunned Mr Bush, was launched on several fronts. There was an online quiz asking Republican voters if they really wanted a “germophobe” who wouldn’t shake hands as a candidate, and a slick video that sought to highlight past Trump positions that paint him more a liberal than a conservative.

The candidate himself took up the cudgel touring a school popular with Cuban families in Miami’s Little Havana the next day. “He attacks me every day with barbarities,” he declared to reporters in Spanish. “He personalises everything. If you’re not totally in agreement with him, you’re an idiot, or stupid, or you don’t have energy or ‘blah blah blah’.”

There are basic political reasons to be assailing Mr Trump. He is getting too far ahead to be doing nothing. A Monmouth University poll showed the business mogul with 30 per cent of Republican support nationally while Mr Bush, who many expected to be the quick frontrunner, had slid still further to just 8 per cent tied with Senator Ted Cruz.

Pledging on Thursday to support whoever emerges next year as the party’s nominee, Mr Trump declared himself impervious to all verbal grenades. “Everybody that’s attacked me has gone down the tubes,” he boasted. The evidence so far is that he’s mostly right. Ask Senators Lindsey Graham and Rand Paul how far lashing out at Mr Trump got them. Or former Governor Rick Perry of Texas.

Donald Trump delivers the keynote address at the Genesee and Saginaw Republican Party Lincoln Day Event (Getty)

The rancour between Messrs Bush and Trump is mutually traded and is of a different order. The latter may still hold some grudge from the eight years that Mr Bush was Florida’s Governor, 1999-2007, and steadfastly stymied his plans to expand – and profit from – gambling in the state, even though he had donated money to him when he was first running for the office.

More likely, Mr Trump knows that for all Mr Bush’s problems, he may yet remain the biggest threat to him, by virtue of the support he still enjoys from the party establishment and the huge war chest his campaign and the political action groups have built, more than $120m.

Mostly Mr Trump limits himself to mocking the brother and son of former presidents as low-energy and soporific. He took a fresh tack berating him for speaking Spanish too much in Little Havana and elsewhere on the campaign trail. “When you get right down to it, we are a nation that speaks English,” he said. “And I think while we’re in this nation, we should be speaking English.”

But political and personal are sometimes hard to pull apart. “When he attacks me personally or disparages my family, you’re damn right I’m going to fight back,” Mr Bush said. The mixture is most toxic when it comes to immigration, the border, Mexicans and, indeed, language choices.

Mr Bush’s wife, Columba, is Mexican and the offence he takes is indeed personal and political. He noted that Mr Trump had retweeted someone saying he been “speaking Mexican” on the trail.

“Those are dog-whistle terms,” he lamented, implying Mr Trump was trying to endear himself to bigots.

“These are divisive terms. If we’re going to win elections, we need to be much more open and hopeful and optimistic than sending signals to prey on people’s angst.”

On ABC News, he launched his most sustained attack. “[He is] trying to insult his way to the White House. It’s not gonna work. People want an uplifting, hopeful message. People come to this country to pursue their dreams. Sometimes they start without speaking English. But they learn English. And they add vitality to our country.

“To say you can only speak English is kind of ridiculous... This is a diverse country. We should celebrate that diversity and embrace a set of shared values. Mr Trump doesn’t believe in those shared values. He wants to tear us down.”

The new ballistic Bush is something supporters have been yearning to see. It remains to be seen if it dents the Trump armour or backfires. He may yet go “down the tubes” too for daring to do it.