Lawmakers are seeking more information about a whistle-blower’s complaint that Mr. Trump asked Ukraine’s president to investigate Joe Biden during a phone call in July. Mr. Pompeo confirmed today that he was on that call.

Related: Senator Mitch McConnell has said that the Senate would have “no choice” but to begin a trial if the House voted to impeach, but our chief Washington correspondent notes that it might not last long.

Go deeper: In the week since Democrats announced their inquiry, Mr. Trump has increasingly described his critics as treasonous, particularly Representative Adam Schiff, the chairman of the House Intelligence Committee.

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Another angle: State parties submitted plans for next year’s Republican National Convention that include changes to reduce the possibility of intraparty divide.