President Trump is due in Minnesota on Saturday, as his campaign plays for an electoral map it had hoped to expand in a matchup against President Biden. Vice President Harris’s nascent campaign, by contrast, is focusing on the six states most likely to decide the 2024 presidential election.

Trump and his vice presidential pick, Senator Vance, will be visiting Minnesota to rally in the state for the first time as a pair, a stop that’s indicative of a campaign hoping to make historic electoral gains for the GOP.

Minnesota is a state that hasn’t supported a Republican for president since 1972, when it voted for President Nixon over Senator McGovern. In that race, McGovern carried only one state, Massachusetts, and the District of Columbia. Since 1932, Minnesota has supported the Republican Party presidential nominee in only three elections.

Travel for Trump, as a former president and current nominee, is planned well in advance, and the decision to stop in Minnesota dates back to a campaign that no longer exists — a matchup between Trump and Mr. Biden — one where it looked like Mr. Biden was flagging in the polls, even in Minnesota.

In mid-July, Trump’s pollster, Tony Fabrizio, charted out an ambitious goal for the Trump campaign, saying it would work to flip Minnesota, Virginia, New Jersey, and New Mexico as well as winning the six main swing states: Pennsylvania, Michigan, Wisconsin, Georgia, Arizona, and Nevada. North Carolina is also expected to be a battleground.

“Those are states that we’re looking at,” Mr. Fabrizio reportedly said at a GOP event. “And believe it or not, there’s another state up north called Maine.”

Since Mr. Fabrizio made these comments, Ms. Harris is now the presumptive Democratic nominee, and the race has narrowed, according to recent polls.  

In their early July survey, the New York Times and Siena College found that Trump led Mr. Biden 49 percent to 43 percent among likely voters and 49 percent to 41 percent among registered voters.

In the latest New York Times and Siena College survey, Trump leads Ms. Harris by just a point nationally among likely voters, 48 percent to 47 percent, and by 48 percent to 46 percent among registered voters — a result within the survey’s plus or minus 3.3 point margin of error.

“It’s a new election,” the Siena College Research Institute director, Don Levy, said of the survey. “This poll taken immediately after Biden dropped out of the race shows Harris opening up a 21-point lead among young voters, previously a Biden weakness, while Trump grabs a 5-point advantage among older voters, a group that Biden had led by three.”

The Harris campaign appears to hope enthusiasm for her candidacy will inspire Black, Latino, and young voters. Her new campaign video, released on Thursday, showed Ms. Harris being cheered on by crowds, to the tune of a Beyonce song that the A-list performer gave Ms. Harris permission to use.

Times and Siena College polling does show, though, that Ms. Harris appears to have carried over some of Mr. Biden’s strength with voters over 65 years old, a core Republican constituency. While Mr. Biden enjoyed 48 percent support among this group in the last survey before he dropped out, Ms. Harris enjoys 47 percent support.

Indeed, as Trump’s campaign visits Minnesota, Ms. Harris’s campaign has issued a roadmap for how it plans to win the 2024 election by redoubling Mr. Biden’s campaign efforts in the six key swing states.

A memo from Ms. Harris’s campaign chairwoman, Jen O’Malley Dillon, who also chaired Mr. Biden’s campaign, published on Wednesday, mapped out a plan “to focus on the Blue Wall states of Michigan, Wisconsin, and Pennsylvania — and the Sun Belt states of North Carolina, Georgia, Arizona and Nevada.”

In the memo, Ms. O’Malley Dillon described a strategy of parlaying Ms. Harris’s popularity with Black, Latino, Asian American, Native Hawaiian, and Pacific Islander voters, as well as her relative popularity with young voters and women, to build a coalition in these states.

“While the Vice President is poised to build on the 2020 Biden-Harris coalition, Trump, on the other hand, has not expanded his support,” Ms. O’Malley Dillon writes. “This has become even more clear in the last month, where he largely failed to win over new voters following the debate and the RNC convention.”

As it stands, it’s not clear whether Trump’s campaign will pull back on its push to win over some blue states like Minnesota. 

In recent days, Republican have doubled down on calling Ms. Harris the “border tsar” while Trump has taken to calling her “nasty” and a “radical left lunatic,” and commenting on her “pole numbers.” House Republicans have also held a behind-closed-door meeting aimed at instructing members to stop making comments about her race.

“They are literally grasping at straws,” a former deputy chairman of the Minnesota Republican Party, Michael Brodkorb, told Politico on the matter. “Republicans desperately wanted to run against Joe Biden.”

He added: “The introduction of Harris into the race, I think, has upended their attacks and their strategies.”