That admission, included in a four-page sworn statement released on Tuesday, contradicted what Mr. Sondland told investigators last month, when he said he “never” thought there was any precondition on the aid. It gives Democrats a valuable piece of evidence for their abuse-of-power case, as Mr. Sondland, the U.S. ambassador to the European Union, is a political supporter of Mr. Trump who has interacted directly with him.

Quotable: “I said that resumption of the U.S. aid would likely not occur until Ukraine provided the public anticorruption statement that we had been discussing for many weeks,” Mr. Sondland said.

Context: Our reporters analyzed key components of the testimony from Mr. Sondland and from Kurt Volker, the former special envoy to Ukraine.

What’s next: Investigators have summoned Mick Mulvaney, Mr. Trump’s acting chief of staff. He is unlikely to cooperate.

Related: Mr. Trump will ask the Supreme Court to rule on his claim that he is absolutely immune from criminal investigation while in office. If the court hears the case, its decision is likely to produce a major statement on the limits of presidential power.