Senator Mitch McConnell, the Republican leader, has told associates he believes President Trump committed impeachable offenses and that he is pleased that Democrats are moving to impeach him, believing that it will make it easier to purge him from the party, according to people familiar with his thinking. The House is voting Wednesday to formally charge Mr. Trump with inciting violence against the country.

At the same time, Representative Kevin McCarthy, the minority leader and one of Mr. Trump’s most steadfast allies in Congress, has asked other Republicans whether he ought to call on Mr. Trump to resign in the aftermath of last week’s riot at the Capitol, according to three Republican officials briefed on the conversations.