“There’s a fair amount of nervousness in the White House and at the State Department about this meeting and how they manage it because they see a lot of potential risks,” said Steven Pifer, a former ambassador to Ukraine who has worked for the National Security Council and the State Department. “There is this gray cloud for the president of the investigations about collusion, so any kind of a deal is going to get the micro-scrutiny of, ‘Is this a giveaway to the Russians?’”…

Cognizant of the perils, the White House has planned Mr. Trump’s itinerary to counter the perception that he is too friendly with Moscow. In Warsaw on Thursday, he will deliver a major speech and meet with Central and Eastern European allies, activities calculated to demonstrate his commitment to NATO in the face of Russian aggression. But there, too, Mr. Trump will be under pressure to do what he refused to in Brussels during his first trip: explicitly endorse, on European soil, the Article 5 collective defense principle that undergirds NATO…

The potential pitfalls are more than theoretical. White House officials recall with dread the images that emerged from Mr. Trump’s May meeting with Foreign Minister Sergey V. Lavrov and Ambassador Sergey I. Kislyak of Russia in the Oval Office, which showed the president grinning, laughing and clasping hands with the Russian officials.