Trump heads to Europe to face nervous NATO leaders

President Donald Trump and first lady Melania Trump board Air Force One, Tuesday, July 10, 2018, at Andrew Air Force Base, Md. Trump is traveling on a weeklong trip to Europe on a four-nation tour, with stops in Belgium, England, Scotland and Finland. (AP Photo/Pablo Martinez Monsivais)
President Donald Trump waves as he walks off after speaking with reporters before boarding Marine One on the South Lawn of the White House, Tuesday, July 10, 2018, in Washington. (AP Photo/Evan Vucci)
First lady Melania Trump looks on as President Donald Trump speaks with reporters before boarding Marine One on the South Lawn of the White House, Tuesday, July 10, 2018, in Washington. (AP Photo/Evan Vucci)

BRUSSELS — President Donald Trump departed Tuesday on a four-nation European tour that has allies fretting over the risk of damage he could do to the decades-old NATO alliance. They’re also worried about his potential embrace of Russia’s Vladimir Putin during a summit in Helsinki.