WASHINGTON — Donald Trump is a narcissist and egomaniac who thinks only about himself and is not a serious candidate for the 2016 Republican presidential nomination, Louisiana Gov. Bobby Jindal said Thursday in a speech that opened a new rhetorical front for Jindal and his own struggling campaign for the White House.

“The idea of the Donald Trump act is great. The reality of the Donald Trump act is absurd,” Jindal said in a speech to the National Press Club that amounted to an 11-minute screed against Trump, the billionaire real-estate developer and reality-TV celebrity who is leading the crowded Republican presidential field in opinion polls. Jindal consistently ranks near the back of the pack in those surveys.

“He is shallow. He has no substance,” Jindal said of Trump. “He doesn’t know anything about policy.”

Jindal reinforced his anti-Trump assault in media interviews and messages from his campaign Twitter account, with one tweet including a video making fun of Trump’s frequent declarations of love for different groups of people.

Jindal also released a campaign commercial drawing on footage of actor Charlie Sheen to mock Trump.

Trump fired back at Jindal with a tweet of his own: “I only respond to people that register more than 1% in the polls. I never thought he had a chance and I’ve been proven right.”

A month ago, Jindal joked that he would start randomly dropping Trump’s name into speeches in order to attract attention, hoping to capitalize on the media’s fascination with the rise of Trump and his boastful, bombastic campaign style. In his Press Club speech Thursday, Jindal called out Trump by name more than 20 times.

Jindal called Trump “a carnival act” and repeatedly referred to him as a narcissist and egomaniac. Like all narcissists, Jindal said, Trump is actually insecure and weak.

Jindal said he liked “the idea of Donald Trump” as an outsider attacking the establishment. But the danger in Trump’s candidacy, Jindal said, is that if Trump succeeds in winning the Republican nomination, he will hand the Democrats victory in the general election and squander a prime opportunity to apply true conservative values to governing the nation and save it from its plunge into socialism under Democratic President Barack Obama.

“It is time for us to tell him, ‘Donald, you are fired,’ “ Jindal said, alluding to Trump’s reality-TV role auditioning job applicants on “The Apprentice.”

The speech could be a preview of a line Jindal may try to take Wednesday, when he is scheduled to participate in a nationally televised debate among the Republican candidates on CNN. Because he ranks outside the top 10 in national polls, Jindal will be relegated to the second-tier debate to be broadcast before the prime-time event headlined by Trump.

Jindal criticized Trump in July for his disparaging comments about illegal Mexican immigrants. Trump dismissed the criticism then, belittling Jindal as a candidate “at zero” in the polls.

Jindal did register zero in four successive national polls conducted from mid-August to early September, according to the Real Clear Politics web site. In a CNN poll taken Sept. 4-8 and released Thursday, he logged 1 percent, placing him in a tie for 12th among Republican candidates and 31 percentage points behind Trump, the leader in the survey.