RNC 2016: Donald Trump's attack dog Chris Christie makes the case against Clinton

The New Jersey Governor also found time to compliment the Republican nominee, which was better than Paul Ryan or Mitch McConnell could do

'Every region of the world has been infected with Hillary Clinton's flawed judgment,' Chris Christie told Republican delegates in Cleveland ((Getty Images))

First Chris Christie was a fierce primary opponent, who mocked and criticised Donald Trump when it still seemed unthinkable that the property mogul could become the Republican presidential nominee. Then he was a sidekick and a wannabe VP, who reportedly begged Mr Trump to put him on the ticket in an 11th-hour phone-call. Now, it appears, the Governor of New Jersey has been tamed, trained and unleashed as the Trump campaign’s attack dog.

Speaking at the Republican Convention in Cleveland on Tuesday night, Mr Christie invoked his past as a federal prosecutor to press the Republican case against Hillary Clinton. As chants of “Lock her up!” raced around the two-thirds-full Quicken Loans Arena, Mr Christie depicted the former Secretary of State as a liar, a fool and an incompetent in a fiery address that he claimed would “hold Hillary Rodham Clinton accountable for her performance and her character.”

Ms Clinton, who is set to accept the Democratic nomination in Philadelphia next week, was “the chief engineer of the disastrous overthrow” of Libyan dictator Muammar Gaddafi, Mr Christie claimed. She was “an apologist” for Boko Haram, somehow responsible for the Nigerian terror group’s kidnapping of hundreds of schoolgirls, he said. She was, he went on, the “inept negotiator” of the Iranian nuclear deal, AKA “the worst nuclear arms deal in American history.”

Insisting that “every region of the world has been infected with her flawed judgment,” Mr Christie turned to the controversy over Ms Clinton’s private email server, which recently earned her censure – but, crucially, not an indictment – from the FBI and the US Department of Justice. As Secretary of State, the New Jersey Governor alleged, Ms Clinton had “cared more about protecting her own secrets than she cared about protecting America’s secrets.”

Amid the assaults on Mr Trump’s opponent, Mr Christie also found time to compliment his own party’s nominee, whom he described as “a strong leader” and a “caring, genuine and decent person… who understands the frustrations and aspirations of fellow citizens.” Yes, he was talking about Donald Trump.

That was more than Paul Ryan and Mitch McConnell could manage, when the GOP’s congressional leaders took to the stage earlier on Tuesday evening. Both had been slow and somewhat reluctant to endorse Mr Trump, and both declined to give him more than a passing mention in their convention speeches.

Urging party unity, Mr Ryan, the Speaker of the House of Representatives, warned Democrats were “offering a third Obama term, brought to you by another Clinton.” He went on: “This year of surprises and dramatic turns can end in the finest possible way,” – not necessarily with a Trump presidency – but “when America elects a conservative governing majority.”

Meanwhile, the best that Mitch McConnell could say for Mr Trump was that he would sign Republican legislation into law. Listing, one by one, a selection of GOP-authored bills that President Barack Obama had vetoed, the Senate Majority Leader repeated the simple, uninspiring mantra: “Donald Trump would sign it."