Republican presidential front-runner Donald Trump unleashed a fusillade of attacks Monday on Gov. Christie, a rival, criticizing him on everything from New Jersey's economy to the George Washington Bridge scandal.

Trump's remarks came in response to a Sunday editorial by the publisher of the New Hampshire Union Leader, which called the celebrity real estate mogul's campaign "an insult to the intelligence of Republican voters."

Trump accused Christie - who was endorsed by the Union Leader and is gaining ground in Granite State polls - of encouraging the publisher, Joseph W. McQuaid, to write the editorial.

"This is the way Chris is," Trump said in an interview with WMUR, a New Hampshire TV station.

McQuaid is "backing Chris Christie, and it's ridiculous to back Chris," Trump said, declaring that New Jersey was the "worst state in the union in terms of economics."

Trump pointed to New Jersey's high taxes and nine downgrades by Wall Street ratings agencies of the state's debt since Christie took office in 2010, echoing a recent criticism of Christie by former Florida Gov. Jeb Bush.

New Jersey's business tax climate ranks last among the states, according to the right-leaning Tax Foundation, a Washington think tank.

Christie has boasted of vetoing tax increases passed by New Jersey's Democratic-controlled Legislature, and argued that the state was worse off before he took office.

Trump also recalled Christie's greeting of President Obama in 2012 when Hurricane Sandy hit the Jersey Shore just before the presidential election, an episode that roiled conservatives.

"He was so warm and so happy to have Barack Obama in the state of New Jersey that I personally think it could have cost [GOP nominee Mitt] Romney the election," Trump said.

Upon seeing Christie interact with Obama, Trump said Monday, he even thought Christie "was going to vote for Obama."

A spokeswoman for Christie's campaign did not respond to a request for comment.

Kentucky Sen. Rand Paul, who is also seeking the 2016 nomination, reprised that line of attack in the first GOP debate in August, accusing Christie of giving Obama "a big hug."

Christie's record in New Jersey had gone mostly unnoticed during the campaign until recently, as the governor started to climb in the polls in New Hampshire, which holds the country's first primary, Feb. 9.

On Monday, Trump also said it was "impossible to believe" Christie did not know about the George Washington Bridge lane closures in September 2013. Trump has suggested as much before.

"Chris can't win because of his past," Trump said. "I don't believe you've heard the last of the George Washington Bridge, because there's no way he didn't know about the closure of the George Washington Bridge, and all of his people are now going on trial in the very near future. And they're going on criminal trial. There's no way he didn't know about it."

Prosecutors say three former Christie allies closed lanes to the bridge as part of a conspiracy to punish the Democratic mayor of Fort Lee because he did not endorse Christie's reelection.

One has pleaded guilty and is cooperating with the government. Two others have pleaded not guilty; their trial is scheduled to begin in April.

Trump attacked Christie even as he lobbed insults at McQuaid, "a real lowlife."

The Union Leader publisher did not respond to a request for comment.

"Trump has shown himself to be a crude blowhard with no clear political philosophy and no deeper understanding of the important and serious role of president of the United States than one of the goons he lets rough up protesters in his crowds," McQuaid wrote in the editorial.

Trump said McQuaid in the past had asked him to play golf, eat lunch at his country club, and place ads in his newspaper.

In addition, McQuaid requested a "strange thing," Trump said. When Christie was demoted to the so-called undercard debate in November, Trump said Monday, McQuaid asked Trump to tweet that Christie belonged on the main stage. (This alleged request came before the newspaper endorsed Christie for president.)

On Nov. 6, a few days before the debate, Trump tweeted, "I think it would be a good idea - and fair - to include @GovChristie & @MikeHuckabeeGOP in the debate. Both solid & good guys. @FoxBusiness."

Trump also has lashed out at Democratic front-runner Hillary Clinton in recent days. During a rally in Michigan the Monday before Christmas, Trump's only public event last week, he used the word disgusting in a reference to the reason it took Clinton so long to return to the debate stage and then said she was schlonged by Barack Obama during the 2008 primary, using a vulgar Yiddish term for penis that he insists simply means "beaten badly."

In an interview with the Des Moines Register last week, Clinton said she was not surprised by the billionaire's swipes and would not directly respond to him. She criticized Trump for "the inflammatory rhetoric that he is using to divide people, and his going after groups of people with hateful, incendiary rhetoric."

"It's not the first time he's demonstrated a penchant for sexism," Clinton told the Register last Tuesday.

Trump on Monday sought to bring former President Bill Clinton into the back-and-forth.

"If Hillary thinks she can unleash her husband, with his terrible record of women abuse, while playing the women's card on me, she's wrong!" Trump tweeted Monday morning.

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This article includes information from Inquirer wire services.