A month or so ago, the 2024 presidential contest looked like a possible blow-out for former President Donald Trump.

Sure, some polls found the race still competitive, and supporters of President Joe Biden were insisting that his performance in the June 27 debate didn’t fundamentally alter the November presidential contest.

But anyone who watched at least a handful of presidential races knew Biden’s disastrous performance had altered the race, putting the incumbent president in a deep hole and creating significant problems for Democratic House and Senate campaigns.

Biden’s exit from the 2024 contest, the Democratic Party’s rallying behind Vice President Kamala Harris, and Harris’s selection of Minnesota Gov. Tim Walz as her running mate has re-made the race and altered its outlook.

Key state polls show that while Trump once held narrow leads in competitive Great Lakes states (particularly Pennsylvania, Michigan and Wisconsin) and competitive Sunbelt states (especially Georgia and Arizona), but now Harris has pulled even — or ahead — of the former president.

It’s unclear whether the upcoming Democratic National Convention will boost Harris’s prospects even more — or whether she has already gotten a “convention bounce” even before the convention has begun.

One thing is certain from Harris/Walz political rallies and survey data — the Democrats now have momentum.

For Republicans, the new political lay of the land is troubling. Harris has turned out to be strong on the stump, and her running mate, while the target of daily attacks from the GOP, has sent a positive message about optimism and “Midwest values.”

While the election’s focus was on Biden for the first six months of the year, it’s now on Trump, who seems to grow nastier and more embittered each day. His language and tone contrasts poorly with the “happy warriors” campaign of Harris and Walz.

Republicans are trying to turn the race around by “swift boating” Walz, much like what they did to former Sen. John Kerry, D-Mass., in the 2004 race, when they turned his highly decorated military record in Vietnam from an asset to a liability. Chris LaCivita, who perfected the strategy in 2004, is a top strategist for Trump.

But Trump is such a polarizing figure that it is difficult to see the former president remaking the 2024 contest into a referendum on Harris’s running mate. As the former president has noted, people vote for or against the top of the ticket, not for the vice-presidential nominee.

While Harris has a narrow advantage now, Trump and GOP strategists still have almost three months until Election Day, when turnout in fewer than a dozen states will determine who will win the White House.

At the end of June, it didn’t look as if turnout would matter. Biden was performing poorly as a candidate, and key Democratic constituencies — ranging from young voters to voters of color — were unenthusiastic about the party’s ticket.

Now, younger voters appear strongly engaged, Black voters have returned to the fold, and both the pragmatic and progressive wings of the Democratic Party look united in their support of their party’s ticket.

But Republicans also remain enthusiastic about their ticket, and they see the economy, immigration and crime as liabilities for Harris. After all, it’s not as if the incumbent vice president has no ties to the Biden administration. She is the administration.

The presidential debates have the potential to shake up the contest, and events that cannot now be anticipated could change the trajectory of the campaign.

But all things being equal, Harris has a slight advantage over Trump. She is likely to be preferred among the so-called double haters, those who disliked both Trump and Biden, and undecided voters are more likely to be attracted to the Democrats’ optimism than the Republicans’ darkness.

Those key voters are also more likely to find Harris and Walz more personally appealing than Trump and his running-mate, Ohio Sen. JD Vance. 

The Aug. 5-9 New York Times/Siena College poll of swing states found Harris with an advantage on key personal qualities, including “has the temperament to be an effective president,” “is honest,” “is intelligent,” and even “will bring the right kind of change.”

Moreover, Trump simply cannot control himself, as his recent attacks on Georgia Gov. Brian Kemp, a Republican, have demonstrated.

Abortion remains a potentially decisive issue for Democrats, and Harris and Walz have shown that they will be aggressive on issues like crime and immigration rather than running away from those Republican issues.

Whatever happens, the 2024 presidential contest has morphed from a decisive Republican victory to a toss-up where Harris has a narrow advantage over Trump. That’s an important change. 

As always, expect some surprises along the way.