On a November evening a dozen years ago, Barack Obama – who at the time was the 46-year-old junior senator from Illinois – appeared at the annual fundraising dinner-rally of the Iowa Democratic party, at which all of the 2008 Democratic presidential contestants were given about 10 minutes to speak. Obama came in as underdog to the frontrunner, Hillary Clinton, but delivered such a barn-burning stemwinder of a speech that he left as the favorite. A little more than three months later, he won the Iowa caucuses – the first major contest on the US presidential campaign calendar – and the rest is history.

None of the Democratic presidential hopefuls who spoke at last week’s Iowa Democratic party Liberty and Justice Celebration pulled off an Obama-level breakout performance. But the one who came closest was Pete Buttigieg, the 37-year-old mayor of South Bend, Indiana. Buttigieg hewed closely to the Obama playbook in making a case for his candidacy, and his Iowa speech seems likely to boost him in the polls at just the moment when the other leading candidates are showing some worrisome weaknesses.

The latest New York Times/Siena College poll finds that among likely Democratic voters in Iowa, Elizabeth Warren now holds a narrow lead, followed closely by Bernie Sanders, Buttigieg, and former vice-president Joe Biden, with the rest of the pack far behind. That finding obviously is encouraging for Buttigieg, who has moved from unknown to contender in just a few months, and for Warren, who has risen steadily throughout the campaign while Sanders stagnated and Biden sank.

But a new Times/Siena survey of likely voters also finds that in the half-dozen battleground states where a close presidential contest is likely to be decided, Biden is the only Democratic candidate who leads Donald Trump, albeit by narrow margins. Sanders trails Trump in every state but Michigan, and Warren is behind in all six states. In separate head-to-head polling in Iowa (the only state where the survey included Buttigieg), Biden trails Trump by one point, Sanders by three, Buttigieg by four, and Warren by six.

These findings are likely to intensify Democratic fears that a Warren-Trump matchup would lead to a repeat of the 2016 debacle. And even with Trump facing continued low national approval ratings and the threat of impeachment, some influential Democrats are so concerned about Biden’s flaws and Sanders’ still-unpopular socialism that they’re dreaming of more compelling candidates entering the race: Oprah Winfrey, perhaps, or New York billionaire Michael Bloomberg (on the theory that it takes one to beat one).

Buttigieg, of course, has his own vulnerabilities. These include his youth – at 37, he is the youngest Democratic candidate and half the age of Sanders and Biden – and relative lack of political experience. And the single biggest question hanging over his candidacy is whether culturally conservative minorities and working-class whites will vote in sufficient numbers for the first openly gay candidate to mount a major presidential campaign. Two October polls found his support among black voters in South Carolina to be between 0 and 1%.

But in a recent interview, Buttigieg maintained that the Democratic primary race ultimately will come down to him and Warren. And Buttigieg and Warren devoted much of their Iowa Liberty and Justice speeches to attacking each other, while being careful not to mention their opponent by name.

As Biden’s stumbles have created an opening in the political center of the Democratic Party electorate, Buttigieg has responded by abandoning his initial attempts to outflank his competitors and repositioning himself as a moderate. In particular, he has criticized Warren for being evasive about how she would pay for her Medicare for All plan, which credible sources estimate would cost between $31tn and $34tn over a decade. Buttigieg’s proposed Medicare-for-all-who-want-it alternative would also represent an expensive advance on the status quo. But by allowing Americans who have private insurance to keep it if they wish – unlike Warren and Sanders, who would eliminate it – Buttigieg can advertise himself as both a progressive and a pragmatist.

Warren, at the Iowa rally, repeated her claim that any policy proposals that don’t match her vision of “big structural change” are a reflection of her more moderate rivals being “either too cynical or too downtrodden to believe change is possible”. Any candidate who doesn’t endorse her preferred policies like Medicare for All or the Green New Deal must therefore be telling Democrats “to dream small and give up early”. And she deemed any unwillingness to embrace her vision of sweeping change to be a cowardly unwillingness to fight or a sellout desire to return to “business as usual”. She charged that “even some people in our own party” think “that running some vague campaign that nibbles around the edges is somehow safe”.

Buttigieg forcefully rejected that charge: “I will not waver from our commitment to our values or back down from the boldness of our ideas.” But, he added, he would also strive “to include everyone in the future we are trying to build: progressives, moderates and Republicans of conscience ready for change. We will fight when we must fight. But I will never allow us to get so wrapped up in the fighting that we start to think fighting is the point.”

He said that he would lead the country toward “real action” by mobilizing “an American majority that is hungry for change, that is done with the division”. And, in sharp distinction to Warren’s focus on the already committed, he appealed to “people of faith” and the majority of Americans “even in the red states” who want politicians to “do something” about gun violence, climate crisis and systemic racism.

While stopping well short of full “OK boomer”, Buttigieg in a subtle way linked his older Democratic rivals with Trump – all part of a generation that has come to prefer “political warfare” to solving crises.

“I did not just come here to end the era of Donald Trump,” he insisted. “I am here to launch the era that comes next.” He defined the ultimate goal of his politics as “the hope of an American experience defined not by exclusion but by belonging”. It’s not naive to talk about hope and belonging, in his view, even in the Trump era, because “I believe these things – not based on my age but based on my experience” of combat, urban revival and growing popular acceptance of same-sex relationships.

Buttigieg is the most articulate speaker and debater in the presidential race. His Iowa address lacked some of the confidence and emotional resonance of Obama’s speech at the same event in 2007 but, even so, Buttigieg evokes many of the same themes that launched Obama to the White House in the last decade. He, too, represents a broader and more inclusive vision of American identity within a context of overall national unity. He advocates for a politics in which some level of persuasion and bipartisanship is still possible, and advances a serious challenge to existing economic and political arrangements that is still rooted in pragmatic idealism. In less than a hundred days, we’ll find out if Iowa’s Democratic voters consider his version of “hope and change” to be the best approach to take on Trump.