12:22

Surely aware that Tuesday’s vote will be his last stand - his last chance to have an impact on this race - Chris Christie is going negative to make his mark, writes Jonathan Freedland in Bedford, NH.

The New Jersey governor’s stump speech delivered just now in Bedford consisted of a barely-veiled attack on Marco Rubio - the man he clearly deems his biggest rival for the support of relatively moderate Republicans.

Without mentioning Rubio by name, he mocked the role of “first term US senators”, arguing that they lack the executive experience essential for the role of the presidency - experience that governors like him have in spades.

“The presidency is not a place for on the job training”, Christie said, adding there was “no owner’s manual” left in the drawer of the desk of the Oval Office.

Implicitly comparing Rubio to Barack Obama, he said the presidency should not be “handed to someone who can read a teleprompter better than anyone else.” He went on to liken the life of a US senator to that of a child at grade school - devoid of any real responsibility.

All that was missing was a repeat of the description Christie offered earlier this week of Rubio as “the boy in the bubble” , unable to function outside the comfort zone of scripted remarks.

Playing to the stereotype of the pugnacious New Jersey pol, Christie promised he “would leave nothing behind” during the hand to hand combat of tonight’s TV debate of Republican candidates.

But he couldn’t go without delivering a couple of swipes at Donald Trump too. “This job cannot go to an entertainer in chief. We need a commander in chief.”

“Showtime is over,” he said. “It’s game time. It’s time to pick a president.”