President Donald Trump plans to build his controversial ballroom as tall as the White House’s main mansion itself, the project’s chief architect told a federal review committee Thursday — a significant change of plans that breaks with long-standing architectural norms requiring additions to be shorter than the main building.

The conversation appeared to defuse a crisis that erupted after President Trump said military action against Colombia “sounds good.”

“It was a Great Honor to speak with the President of Colombia, Gustavo Petro, who called to explain the situation of drugs and other disagreements that we have had,” Trump posted on his social media s...