President Donald Trump went off script Thursday to rant about Democrats and impeachment efforts, saying they have “betrayed our country” during a campaign rally in Dallas.

“At stake in this fight is the survival of American democracy itself. Don’t kid yourself,” Trump told supporters. “They are destroying this country, but we will never let it happen, not even close. For three straight years, radical Democrats have been trying to overthrow the results of a great, great election.”

As the Democrats’ impeachment inquiry into the president continues to develop, Trump has upped his defenses by attacking his opponents. In Dallas, he went after House Speaker Nancy Pelosi (D-California) as well as the anonymous whistleblower who raised the alarm that Trump inappropriately used his power to pressure Ukraine for political gain.

“I really don’t believe anymore that they love our country. I don’t believe it. Crazy Nancy. That crazy Nancy, she is crazy,” Trump said. “They come after me, but what they’re really doing is they’re coming after the Republican Party and what they’re really, really doing is they’re coming after and fighting you, and we never lose.”

He ranted about the whistleblower, demanding to have his or her identity revealed.

“What about the whistleblower? The whistleblower got it all wrong,” Trump said. “Who’s the whistleblower? We have to know. Is the whistleblower the spy?”

Trump has previously alluded to charges of treason against the whistleblower and all officials who provided information to the whistleblower.

“I want to know who’s the person who gave the whistle-blower the information because that’s close to a spy,” Trump said in September. “You know what we used to do in the old days when we were smart with spies and treason, right? We used to handle it a little differently than we do now.”

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The impeachment probe has gained momentum, after a series of closed-door testimonies by current and former White House officials.

The chairmen overseeing the investigation have been generous in issuing subpoenas, even though the White House has pressed officials to disregard them.

Marie Yovanovitch, the recalled ambassador to Ukraine, testified last Friday about her removal and U.S. involvement in Ukraine. Deputy Assistant Secretary of State George Kent testified to House investigators Tuesday. Michael McKinley, a former aide to Secretary of State Mike Pompeo testified to House investigators Wednesday. Former U.S. ambassador to the European Union, Gordon D. Sondland testified Thursday.

Five more Trump officials have been called to testify next week.

Trump has tried to block the testimonies of other officials and consistently expresses his belief that the inquiry is a “total witch hunt.”