A Republican member of the House of Representatives spent Saturday clarifying his support for congressional oversight of a whistle-blower’s complaint against President Trump, which the lawmaker’s office contended was not the same as endorsing the impeachment inquiry being led by Democrats.

The congressman, Mark Amodei, rejected the distinction that he was the first Republican House member to support the inquiry, with his spokeswoman , Logan Tucker, saying that the word “inquiry” gave the wrong impression that the congressman supported Mr. Trump’s impeachment.

That could be problematic for Mr. Amodei, who is chairman of Mr. Trump’s re-election campaign in Nevada, a state the president lost by about 27,000 votes to Hillary Clinton in 2016.

Mr. Amodei spoke with Mick Mulvaney, the acting White House chief of staff, on Friday to clarify comments he had made earlier in the day during a conference call with reporters from his home state, Ms. Tucker said.