Which is why returning to Washington, as Biden does Tuesday, can be a nasty shock. Globetrotting is one thing. Pour more money and weaponry than any other country into Ukraine's fight against Russia? Biden did that at the stroke of a pen while in South Korea on Saturday.
Poke China with a vow to defend Taiwan against invasion, even if that's not exactly US policy? A simple "yes" to a reporter's question Monday about whether this could happen set the diplomatic world abuzz.
How about bringing 13 countries -- accounting for 40 percent of global GDP -- into a new trade framework that only hours earlier skeptics said would struggle to attract applicants? He did that in Tokyo on Monday too.
But back in the White House, Biden will come back to earth.
Air Force One will touch down at Joint Base Andrews outside Washington and, as if by magic, Biden the globe-striding giant will shrink into Biden, the deeply unpopular leader, blamed for everything and whose Democratic party looks likely to lose power in a few months. It's whiplash that many US presidents have suffered -- and especially acute for Biden.
Unparalleled American clout
The 79-year-old took office in 2021 with big dreams. At home, he wanted to heal the "soul" of America, unite the country and bring back old-fashioned centrist politics after four wrecking ball years of Donald Trump. Abroad, he wanted to take on what he calls an existential threat from autocratic regimes in places like Russia and China.
Sixteen months later, the first job's not going too well.
Domestic policy depends heavily on congressional approval, and Democrats have only the slimmest of possible majorities in Congress, with just two centrist Democratic senators repeatedly blocking Biden's goals.
Come the midterm elections in November, polls show even that fragile advantage will likely be annihilated by vengeful Republicans, ensuring a miserable next two years for the oldest person ever in the presidency.
Job number two, though, is going better -- and that's not necessarily a surprise. Presidents get to call the shots on foreign policy, all while benefitting from extraordinary, almost imperial levels of logistical support.
In Seoul and Tokyo, Biden roared through the streets in motorcades comprising dozens of black, specialized vehicles flown in by advance teams. Or he simply skipped traffic in his Marine One helicopter.
And everywhere he flew in Air Force One, sprawling US military installations awaited. Refueling in Alaska, then landing at Osan Air Force Base outside Seoul and Yokota Air Force Base in Tokyo, the plane's itinerary alone told the story of unparalleled American clout.
Back home, cold reality awaits. While Biden was traveling, a new poll came out showing 39 percent support, his lowest approval rating yet. The country is up in arms over the highest price increases in 40 years.
And Biden is being blamed for everything, including things like the disappearance of baby formula from supermarket shelves after a product recall he has little ability to influence. The foreign trip wasn't always smooth, either.
Biden's comment about defending Taiwan was applauded in some quarters but criticised as muddled in others, while for some analysts, the 13-country trade initiative was just hot air.
Still, Sue Mi Terry, director of the Asia Program at The Wilson Center in Washington, says Biden deserves good marks for his performance on the world stage. He's "succeeding more than he is failing," she said, listing a "solid" performance in building alliances against China and the "good job" of leading the diplomatic response against Russia in Ukraine.
The real problem is that separating those two spheres -- domestic and foreign -- might not always be possible. "Foreign leaders definitely pay close attention to US politics and they are well aware of Biden's sagging poll numbers," Terry said, explaining the damage done to a president's credibility.
And this will worsen "on the world stage if Republicans win the midterm elections," she said. So "Biden is making the best of the situation, and to some extent, US allies are all the more eager to work with him now while they still can."