BEDFORD, N.H. — New Jersey Gov. Chris Christie warned on Wednesday that U.S. Sen. Kelly Ayotte’s re-election chances will be at risk if New Hampshire Republicans don’t unite behind Donald Trump as their party’s presidential nominee.

“If we are not unified at the top of the ticket, it will affect what happens to Kelly Ayotte on Nov. 8,” Christie said.

Christie, who failed in his own 2016 presidential bid, offered the harsh assessment at the New Hampshire Republican Party’s post-state primary unity breakfast. It marked his first return to New Hampshire since he placed sixth in the state’s February presidential primary despite spending more time in the state than nearly any other candidate.

Ayotte left the breakfast before Christie began his speech. She said she will vote for Trump but is not endorsing him, and she has publicly spoken out against some of his remarks.

Christie was the first of Trump’s vanquished GOP rivals to endorse him despite pitching him as unprepared to lead during the primary contest. He said Wednesday he sees it has his duty to help get Trump, a billionaire New York real estate mogul, ready for the presidency, suggesting Trump has something to learn about conservative governing.

“I made my decision (in February) that Donald Trump was going to be the nominee of our party and it was the job of those people who had been governing and leading the conservative fight in the states to get him ready,” Christie said.

Christie said it’s “mystifying” to see some Republicans announce support for Trump’s main rival, Democratic former U.S. first lady, New York U.S. senator and U.S. secretary of state Hillary Clinton, and he sternly told the crowd the election represents a binary choice.

“If you are a Republican and you are not working for Donald Trump over the next 55 days, you are working for Hillary Clinton,” he said.

Christie’s visit to New Hampshire marked one of his first solo appearances on behalf of the Trump campaign. He often appears with Trump when he hits the trail for duties not related to his governorship.

His sixth-place performance in the New Hampshire primary marked a stunning fall for a candidate who once appeared poised to take first or second place. He joked on Wednesday about the months he spent cajoling, begging and pleading with New Hampshire voters to back him.

“Weeping for you if necessary, whatever,” he said.

But he offered his defeat as a lesson on the need to unify behind Trump and the rest of the state’s Republican ticket.

“We need to put aside the drama and the emotion of the primary season,” he said. “We need for the last 55 days to focus ourselves on what the real fight here is.”

Green Party nominee Jill Stein and Libertarian nominee Gary Johnson also are seeking to win the White House in the Nov. 8 election.