Donald Trump was in an SUV speeding to the airport at 6:30 Friday morning when he called campaign Chairman Paul Manafort.

They discussed the good news—favorable reviews of a speech the Republican presidential nominee had given the night before in North Carolina. Then they turned to the bad news: Mr. Trump expressed concern that the attention being paid to consulting Mr. Manafort had done for a pro-Russian party in Ukraine had become a major distraction that could hurt his campaign.

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