President Trump lashed out at Democrats on Wednesday, calling candidates for the 2020 nomination “clowns” and predicting a depression if any of those running becomes president.

The president’s criticism came hours after a dozen candidates faced off for the fourth Democratic debate ahead of the primary season. Sen. Elizabeth Warren of Massachusetts became the focal point of attacks by other contenders, an apparent response to her rise in the polls. Warren and her Medicare-for-all plan came under attack when she refused to say whether it would require raising taxes on the middle class.

“Our record economy would crash, just like in 1929, if any of those clowns became president!” Trump tweeted, taking a page from the new movie, "Joker," in which Bruce Wayne's father, Thomas, calls people clowns.

Trump also railed against the House impeachment inquiry, calling it a witch hunt, despite a reported White House review of the call that led to the investigation.

Democrats opened the inquiry based on a whistleblower’s complaint concerning a call Trump made to Ukraine’s president in which he asked Volodymyr Zelensky to investigate former Vice President Joe Biden. The New York Times reported White House advisers have opened a fact-finding review on why White House counsel John A. Eisenberg hid a rough transcript of the call in a computer system generally reserved for secret communications.

Trump was a main target as the Democrats squared off during the three-hour confrontation. Sen. Amy Klobuchar skewered Trump’s “Make America Great Again” slogan, saying his actions are making “Russia Great Again.” South Bend (Ind.) Mayor Pete Buttigieg said impeaching Trump and expelling him from office may feel like a happy thought, “but really think about where we’ll be: vulnerable, even more torn apart by politics than we are right now.”

Businessman Tom Steyer called Trump a criminal while former Rep. Beto O’Rourke of Texas accused Trump of betraying military veterans.

Biden called Trump’s decision to pull U.S. troops out of Syria, opening the way for Turkey to attack the Kurds, “shameful.” All the candidates agreed Trump has damaged the U.S. standing in the world and destroyed the trust of its allies.

Sen. Kamala Harris of California urged Twitter to suspend Trump’s account for violating the site’s rules.

Twitter responded to Harris’ challenge by saying though world leaders “are not above our policies,” their comments need to be analyzed carefully.

“Our mission is to provide a forum that enables people to be informed and to engage their leaders directly,” the social media platform explained.

“We assess reported Tweets from world leaders against the Twitter rules, which are designed to ensure people can participate in the public conversation freely and safely.

“We focus on the language of reported Tweets and do not attempt to determine all potential interpretations of the content or its intent.”

Twitter said it does not condone tweets that promote terrorism or clear and direct threats of violence, reveal private information or share intimate photos or videos without consent, or material involving child sexual exploitation or promoting self-harm.

In other campaign news, Biden entered the fourth quarter with less money than either Warren or Sen. Bernie Sanders of Vermont while Trump’s war chest shattered fundraising records in the third quarter.

Freshman Rep. Alexandria Ocasio-Cortez, D-N.Y., seen as a leader of the progressive wing of the Democratic party, was slated to endorse Sanders for the 2020 presidential nomination.