Donald Trump sets foot on foreign soil on Saturday for the first time since he was elected, marking the start of a nine-day trip fraught with pitfalls for a president known to depend on home comforts.

川普总统在星期六踏上了第一次当选后的出国拜访。开启了对于川普总统这样恋家的人来说为期9天的苦难之旅。

An ambitious itinerary will take him from Saudi Arabia to Israel and on to Belgium, Italy, and the Vatican, with Nato and G7 summits towards the tail end of the trip.

本次丰富的行程将会从沙特开启，历经以色列，比利时，梵蒂冈，最后以G7和Nato峰会收官。

George W Bush had visited two countries by this point in his first term and Barack Obama nine. But wary of spending as much as a night away from his own bed, Mr Trump has kept even domestic travel to a minimum.

布什在同时期任期时已经拜访了2个国家，奥黑9个。但是认床的川普把国内的旅行都控制在最小范围。

Instead he has spent his presidential honeymoon mostly hunkered in the White House or his Mar-a-Lago resort, dogged by a deepening scandal over his campaign's ties to Russia.

与之相反的，他上任蜜月后一直留恋在白宫或是他的度假胜地，躲避不断发酵的丑闻-俄罗斯与他的胜选有关。

As a candidate he told reporters he was unlikely to travel abroad much because America required his undivided attention, but the evidence suggests the 45th president has always been a homebody.

在竞选期间，他就向记者称述 他不大经常性的出国，因为美国需要他全神贯注。但是有证据表明，45届总统一直是恋家的男孩。

On the campaign trail he returned to his gilded Manhattan apartment after nearly every rally, by helicopter or private jet, and former business aides say he was always reluctant to spend time anywhere but a Trump-branded property.

"Trump is a man who likes to be on the couch with a good cheeseburger," Roger Stone, a long-time friend and former adviser, told Reuters during the campaign. "He likes being in his own bed, even if it means coming into (New York airports) Teterboro or LaGuardia after midnight."

But it's a long way from the Vatican to the White House. So, unable to bring Trump back to the US, the president's staff has made plans to bring the US to Trump. In Saudi Arabia he will be served steak with tomato ketchup - his favourite meal - alongside the local cuisine prepared by his hosts, the AP reported.

The president passed up a typical first foray to Canada or Mexico - an easy option taken by every president since Reagan - and initial plans for a short trip to Europe ballooned into a nine-day, five-country tour taking in two major summits.

"This is an enormously complex undertaking, there are so many things that will be challenging for Trump it's headspinning," said Daniel Benjamin, who travelled extensively on Air Force One as Bill Clinton's foreign policy speechwriter.

"The first thing is simply the pace. If you look at how Trump spends his days in the White House, it seems to be an enormous amount of time watching TV and not much else. But these trips are punishing, he will be meeting an enormous number of people and it requires tremendous energy and focus - not his strong suit."

The president's team has reportedly attempted to build downtime into his schedule wherever possible, and instructed foreign delegations that he prefers short presentations with lots of visual aids.

His limited attention span is said to have already affected preparation for the trip. Aides threaded the president's own name through the paragraphs of a two-page briefing memo in order to hold his interest, the New York Times reported on Friday.

Preparations will also have been damaged by the Russia inquiries and the firing of FBI director James Comey, as well as a lack of senior leaders in place at the State Department, where the administration has failed to fill gaps under Secretary of State Rex Tillerson.

One of the president's first duties on this trip will be to deliver a speech on religion in Saudi Arabia - reportedly being drafted by Trump adviser Stephen Miller, the man behind the administration's misfired travel ban.

"Going to Saudi Arabia and talking about Islam is like going blindfold into a minefield, on a pogo stick," said Mr Benjamin.

"Speeches would normally be worked on for four to six weeks in advance, but this is an understaffed White House that has been focused on a fusillade of bad news. So unless they've discovered a secret for no sleep, they must be seriously distracted."

Mr Trump's team will be expected to respond from the road to breaking news and political developments at home and abroad, as well as shepherd the president around any potential own goals or gaffes in front of his hosts.

Presidents past have suffered indignities on foreign trips. George W Bush famously attempted to leave a press conference in China via a locked door, and had a shoe thrown at him at a press conference in Iraq. His father, George HW Bush, vomited into the lap of the Japanese prime minister.

Departing from protocol can lead to mishaps. President Obama was criticised for bowing to Japanese Emperor Akihito and Michelle Obama for hugging Queen Elizabeth. George W Bush - who had his fair share - gave German Chancellor Angela Merkel an ill-advised and unwelcome shoulder massage.

But if Mr Trump's team can steer him ably around these pitfalls, he does have a couple of things going for him. He is taking the majority of his senior staff and the first lady, which may offer a sense of stability.

Mrs Trump, who was born in Slovenia and lived in France and Italy before moving the US, is a more seasoned traveller. Mr Trump visited her home country once, and stayed just one evening. "At least I can say that I went," he later said.

He has also chosen to begin in a part of the world that will offer a warm reception. The president's hard line on Iran, along with other overtures, has endeared him to Saudi Arabia and to Israel, and both countries have a vested interest in good relations with the new administration.

"He is going to want it to be successful and they're going to want it to be successful, and my guess is it will be successful," said Stephen Hadley, a former national security adviser who travelled widely with George W Bush.

"The truth is that nobody is prepared for being president until they're the president. The flipside with Trump is that this is a guy who's been in the public eye for 30 years, who's very media savvy and who likes to be in the limelight."

Visiting the Pope "would be hard to get wrong", said Mr Hadley, but at the two summits the president may face testy exchanges with leaders aggrieved by his anti-EU proselytising, anti-refugee sentiment and high-handed demands for greater Nato payments. Mr Trump had what appeared to be a frosty meeting in Washington in April with Mrs Merkel, who he openly criticised during the campaign.

Added to that, this is a long and busy first trip for any president. "There is real risk that he will tire towards the end," said Mr Hadley.

"At these summit meetings you might have 28 heads of state and government and they all want to say something, and the president has to sit and listen to all of them. That will tax any world leader, let alone one who finds it hard to sit still."