President Trump’s lawyers believe they can weather a “negative” report from special counsel Robert Mueller and are prepared to rebut the conclusions, Rudy Giuliani, one of Mr. Trump’s attorneys, said in an interview.

Mr. Giuliani said the president is open to talking to Mr. Mueller under limited conditions but, in a new development, said Mr. Trump wouldn’t sit for an interview after Sept. 1 because that could interfere with the midterm elections.

Last week, the president’s lawyers sent Mr. Mueller a proposal indicating that Mr. Trump would take questions about collusion with Russia in the 2016 elections but not about obstruction of justice after he took office. Obstruction questions, his lawyers worry, could become a trap for perjury accusations.

“I think we made the offer we can live with,” Mr. Giuliani said.

Mr. Mueller’s office declined to comment. Should he reject the offer, Mr. Mueller could subpoena the president, setting in motion a legal showdown.