House Speaker Nancy Pelosi (D-Calif.) said on ABC's "This Week" Sunday that she does not regret waiting three weeks to transmit the articles of impeachment against President Trump to the Senate, arguing that the tactic has "produced a very positive result."

The exchange:

GEORGE STEPHANOPOULOS: "Second thoughts about holding on for three weeks."

PELOSI: "No, no, no. We feel that it has produced a very positive result in terms of additional emails and unredacted information that has come forward. Bolton has said that he will testify if subpoenaed by the Senate. Other information that has come forward. More importantly, raising the profile of the fact that we need to have witnesses and documentation, and if we don't, that is a cover-up."

Why it matters: Critics have argued that withholding the articles undermines the Democratic case that impeachment is urgent and that Trump poses a threat to national security.

Pelosi counters that news that former national security adviser John Bolton is willing to testify in the Senate trial — as well as reporting from the New York Times and Just Security about the administration's freeze on Ukraine military aid — shows that the delay has paid off.

She believes that these revelations have put pressure on moderate Republicans to support calling witnesses in the Senate trial. She called Majority Leader Mitch McConnell's (R-Ky.) decision to sign onto a resolution to dismiss the case evidence of a "cover-up."

Driving the news: Pelosi said Friday she will ask House Judiciary Chairman Jerry Nadler (D-N.Y.) to "be prepared“ to name impeachment managers and to send the articles to the Senate next week.

What they're saying: Trump on Sunday, just minutes before Pelosi's interview on ABC, called the speaker "Crazy Nancy" in a tweet and asked Stephanopoulos to ask her a question about House Intelligence Chairman Adam Schiff (D-Calif.).

"I'd like to talk about more pleasant subjects than the erratic nature of this president of the United States," Pelosi said. "But he has to know that every knock from him is a boost."

Pelosi said she initially held off on impeaching Trump because she believed he was "not worth impeaching." His conduct toward Ukraine changed her mind, she said.

"Everything he says is a projection," Pelosi added. "When he calls somebody crazy, he knows that he is."

Go deeper: