Jeb Bush blasts '˜vulgar' Donald Trump as he endorses Ted Cruz

Former Republican presidential hopeful Jeb Bush has said he is endorsing Ted Cruz for president.

Republican presidential candidate Ted Cruz (left) shakes hands with Jeb Bush. Picture: AFP/Getty Images

Bush tweeted that “Ted is a consistent, principled conservative who has shown he can unite the party”.

He added on his Facebook page that Republicans “must overcome the divisiveness and vulgarity Donald Trump has brought into the political arena” or risk losing to Hillary Clinton.

Republican Trump and Democrat Clinton held their leads in the battle for their parties’ 2016 presidential nomination in the latest state-by-state voting as the Islamic State terrorist organisation inserted itself deeper into American politics with the attacks it claimed in Belgium.

While both frontrunners scored victories in the night’s biggest prize of Arizona, Democratic challenger Bernie Sanders won caucuses in Utah and Idaho and Republican Ted Cruz claimed his party’s caucuses in Utah.

But Cruz drew a sharp rebuke from Muslim Americans and civil rights groups in his response to the Belgium attacks when he said that authorities should be empowered to “patrol and secure Muslim neighbourhoods before they become radicalised”.

Both Clinton and Trump seized the attacks on the Brussels airport and metro system that left dozens dead as a chance to level bitter assaults on one another.

“This is about not only selecting a president, but also selecting a commander-in-chief,” Clinton said in Seattle as she condemned Trump by name and denounced his embrace of torture and hardline rhetoric aimed at Muslims. “The last thing we need is leaders who incite more fear.”

Trump, in turn, branded Clinton as “incompetent Hillary” in an interview with Fox News as he discussed her tenure as secretary of state. “Incompetent Hillary doesn’t know what she’s talking about,” the billionaire businessman said. “She doesn’t have a clue.”

Clinton and Trump’s Republican rivals piled on with questions about his temperament and readiness to serve as commander in chief, and condemned his calls to diminish US involvement with Nato. Belgium is a Nato ally.