BEDFORD, N.H. — This year’s Republican presidential campaign is where hope and optimism go to die. Don’t pretend that Donald Trump is an exotic outlier. His spirit haunts a party that can’t get enough of gloom and fear.

Among the GOP candidates, no one started out more optimistic about the United States than Marco Rubio. The Florida senator’s campaign slogan still promises “A New American Century.” He smiles broadly from the cover of his upbeat 2015 book, “American Dreams: Restoring Economic Opportunity for Everyone.” You can almost hear the cheerful guy in the bright red tie saying, “Yes we can.”

The conservative writer Mitchell Blatt sensed this when he called Rubio “the Republican Barack Obama.” He meant it as a compliment. “A Republican Obama,” Blatt wrote last fall, “is just what the Grand Old Party needs to face a changing electorate.”

But since the beginning of the year, a new Rubio has appeared, a man given to funereal orations about the passing of the old America. It was this candidate who spoke last week to a packed living room gathering at the lovely home of Shannon McGinley in this postcard-perfect New Hampshire town.

“Something’s happening,” Rubio declared, and the something, voters have been telling him, isn’t good: “This doesn’t look like my country anymore. I don’t recognize America. What’s happening to my country? I feel left behind. I feel out of place.”

President Obama, he said, wants “to fundamentally change America into a very different type of country,” and Rubio’s bill of particulars against the incumbent was long: He “doesn’t believe in free enterprise,” “looks with great suspicion at people with traditional values,” sees the Constitution as “a stale and outdated document” and views the United States as “an arrogant global power, a nation that needs to be cut down to size, that needs to be humbled.” We are now, Rubio said, echoing Trump, “a nation in decline.”

And then an ominous warning: “If we get this election wrong, there may be no turning back for America.”

Rubio still tacks on hopeful stuff at the beginning and end of his stump speech, since his whole pitch is that he’ll manage to fix everything. But Rubio’s new path is revealing — about him, and about the current shape of the GOP contest. He senses that the conventional description of the Republican contest is both wrong and not helpful to him. Rubio is typically cast as running in an “establishment lane” with Jeb Bush, John Kasich and Chris Christie. Trump is a lane unto himself, and Ted Cruz has largely been ceded his own lane on the right as potential competitors have fallen back (Mike Huckabee, Rick Santorum) or withdrawn (Bobby Jindal, Rick Perry).

This take on the contest doesn’t appreciate how complicated voters are. Rubio, for example, is clearly in competition with Cruz for many conservative voters. Some of them were represented in the McGinley living room, including Rick and Johanne McQuaide. Cruz and Rubio, said Rick McQuaide with approval, are both proposing “a very different direction for the country.” Both McQuaides were pondering whether Rubio might be the better messenger.

Rubio wants to fight Cruz for the hearts of voters like the McQuaides, and the Florida senator’s tougher talk is clearly designed to stem a Cruz surge, not only in Iowa but also, according to some polls, in states as diverse as California and South Carolina. Some current Trump-leaning voters could also come loose, and both Rubio and the proudly tough-talking Christie have their eyes out for them.

The risk for Rubio is that his embrace of Cruz-Trumpism (or Trump-Cruzism) could open space for Bush and Kasich on the nearer parts of the GOP right and among independents who can vote in the Feb. 9 New Hampshire primary.

Still, Rubio is not foolish to bet that there is no such thing as excess when it comes to pessimism about Obama’s America. He’s calculating that if he secures the nomination, he’ll have plenty of time to go back to being that hopeful man with the big grin, the red tie and the yes-we-can attitude.

E.J. Dionne is a columnist for The Washington Post. His email address is: ejdionne@washpost.com. Twitter: @EJDionne.