Senior Republicans attack Trump

The scathing letter, published Wednesday, said a Donald Trump presidency would undermine US security and diminish America's standing in the world.

"Mr. Trump's own statements lead us to conclude that as president, he would use the authority of his office to act in ways that make America less safe," the letter says.

"Furthermore, his expansive view of how presidential power should be wielded against his detractors poses a distinct threat to civil liberty in the United States."

The letter goes on to call the billionaire businessman "fundamentally dishonest" and criticizes his "equation of business acumen with foreign policy expertise."

The document was signed by 60 senior Republicans, including Robert Zoellick, former head of the World Bank and deputy secretary of state; Michael Chertoff, former US Homeland Security Secretary under Presidents George W. Bush and Barack Obama; Dov Zakheim, a top Pentagon official under Bush; and Philip Zelikow, the director of the 9/11 Commission. Former ambassadors, intelligence and nuclear experts also signed the letter.

Their warning, which was posted on a blog site called War on the Rocks, comes after Trump won the largest number of state nominating contests on so-called Super Tuesday, consolidating his position as likely Republican presidential nominee.

A potential backfire?

The signatories to the document also attacked Trump's "hateful, anti-Muslim rhetoric," his approach to trade, his "admiration for foreign dictators such as Vladimir Putin," and his insistence that Mexico pay for a wall on the US border to keep illegal migrants out.

The letter adds to a growing chorus of establishment Republicans attempting to derail Trump's path to the nomination. Bryan McGrath, adviser to Mitt Romney's unsuccessful 2012 Republican presidential campaign, helped organize the effort. He said at least two people declined to sign the letter over concerns it could boost Trump's position as an anti-Washington candidate.

Kurt Volker, who was a permanent representative to NATO under Bush, said he didn't sign his name.

"My concern is that it's not smart for the intelligentsia - the national security intelligentsia - to come out and bash Trump, the candidate," Volker said. "He would use that as a tool, saying: 'Here's the establishment. More of the same. They're afraid of me. I can do better.' He would actually use it as a bragging right."

Others who declined to sign said they feared the attack on Trump could benefit the Democrats.

Former presidential nominee Romney is expected to challenge Trump in a speech on Thursday in Utah, but it's unclear what impact his words will have on voters. Meanwhile, Republican candidates will have a chance to make their case to voters in Thursday night's prime-time debate.

Alarm around the world

Trump's series of victories in the Super Tuesday primaries also prompted strong reactions from the international press.

"The Trump candidacy has opened the door to madness: for the unthinkable to happen, a bad joke to become reality," German business daily "Handelsblatt" wrote in a commentary on Thursday. "What looked grotesque must now be discussed seriously."

According to Alexander Dugin, a Russian nationalist ideologue with close ties to the Kremlin, Trump "is sometimes disgusting and violent, but he is what he is. It is true America."

"To consider Donald Trump a political clown would be a severe misconception," said Austria's "Salzburger Nachrichten."

The daily predicted that Trump's ideas "would bring major dangers for the USA and the world ... basically a nationalist-chauvinist policy that would make America not great but ugly, and risk the stability of the international order."

Writing in the Financial Times of London, Martin Wolf argued it would be a "global disaster" if Trump made it all the way to the White House.

"Mr. Trump is a promoter of paranoid fantasies, a xenophobe and an ignoramus. His business consists of the erection of ugly monuments to his own vanity," Wolf wrote. "Mr. Trump is grossly unqualified for the world's most important political office."

nm/kms (Reuters, AP)