NASHUA, N.H. - Bill Clinton used to say that elections are about the future, but his first solo 2016 campaign appearance on his wife's behalf here Monday was more a safe, sepia-toned reminiscence -- of the prosperity the country enjoyed when he was president during the 1990s, of her work as Arkansas first lady a decade before that, and of how intriguing he found her when she was a rare woman at Yale Law School in the 1970s.

How to use the 42nd president in Hillary Clinton's campaign to become the 45th has always been something of a conundrum. With his star power and his gifts as a speaker, he has the potential to be one of her biggest assets. But with that has always come a host of worries, including that he might outshine her, or veer off script, as he often did in her 2008 campaign.

So his first events were cautious and subdued, a test of how well he plays the supporting actor.

No surprise, the early reviews from the Republicans were harsh.

"Who's running? Her or him?" asked New Jersey Gov. Chris Christie (R), who was holding his own campaign event in nearby Manchester.

Christie, who appears to be gaining momentum here in his bid for the GOP nomination, seemed to suggest that it was presumptuous for a candidate's spouse -- even one who once sat in the Oval Office himself -- to be talking about U.S. foreign aid to fight malaria and tuberculosis, or to be speculating on future U.S. Supreme Court nominations.

There was also additional incoming fire from GOP front-runner Donald Trump, who told CNN several hours before Clinton's first appearance that the former president was "one of the great women abusers of all time," and that Hillary Clinton was his "enabler."

Trump's comments referred to the Monica Lewinsky scandal, in which Bill Clinton's extramarital affair with a White House intern led to his impeachment.

"Hillary was an enabler, and a lot of things happened that were obviously very seedy. He was impeached, for heaven's sake," Trump said.

Clinton took no questions during his half-hour appearance here. However, NBC News's Andrea Mitchell got one in as the former president exited the gymnasium at Nashua Community College.

"How do you feel about the kind of campaign Donald Trump is running, sir?" Mitchell asked.

Clinton paused, and said: "The Republicans will have to decide on who will be nominated. How I feel is only relevant once they pick a nominee. We're trying to win a primary. We've got to do that first."

Hillary Clinton is a formidable favorite to do that, but here in New Hampshire, she has been running behind in most polls against Sen. Bernie Sanders of Vermont.

"She's been here a lot, worked hard. That's all you can do. These people are really fair," Clinton said, though he added: "No candidate who borders New Hampshire has ever lost a primary here, expect when Howard Dean lost to John Kerry because they both did. "

"But I think she can," her husband said. "They've been good to us."

Indeed, New Hampshire has a special place in the chronicle of Clinton resiliency.

The Granite State was where then-Arkansas Gov. Bill Clinton, beset by scandals over an extramarital affair and his efforts to avoid the Vietnam draft, pulled out a better-than-expected second-place finish and resurrected his 1992 presidential campaign.

Sixteen years later, Hillary Clinton's victory here -- a shock, considering the fact that Barack Obama was leading her by a double-digit margin in polls on the eve of the primary -- kept her bid alive after the drubbing she had taken in the Iowa caucuses.

"We know it's a New Hampshire primary now. You know why? It's cold. It's snow. And Bill Clinton's here," community college President Lucille Jordan said in her introduction.

Nearly a quarter-century after New Hampshire primary night when he pronounced himself the "comeback kid," Bill Clinton is grayer and thinner. His voice was so raspy that technicians had to up the volume to make him audible in the modest-sized gymnasium.

But the audience of 720 people did not seem to mind. Some carried signs and buttons that read "New Hampshire [hearts] Bill and Hillary." And dozens waited with copies of Clinton's memoir "My Life" and his book "Giving," hoping to have them signed by the former president.

"He's taken a much calmer persona," said Mary McDermott, 61, who has seen the former president in her state before. "And I kind of like it, to be honest. Because he's not running, so he's letting her stand on her own."

"Obviously they've been together for 45 years. I like how he talked about the history that a lot of younger people didn't know she did," she added.

In his half-hour speech, Clinton made only a glancing, indirect reference to Trump, saying: "I'm a happy grandfather. I'm not mad at anybody."

He focused instead on his wife's fitness for the Oval Office: "I do not believe in my lifetime anybody has run for this job at a moment of greater importance who was better qualified by knowledge, experience and temperament to do what needs to be done."

Afterward, he spent an hour greeting the noontime crowd at Puritan Backroom restaurant in Manchester.

He reflected, a bit wistfully, on his time in the White House: "Even the bad days were good.