WATCH: Harris speaks in North Carolina as Democrats debate Biden’s fitness for campaign

Vice President Kamala Harris delivered campaign remarks in Raleigh, North Carolina on Thursday as Democrats continue to debate whether her running mate, President Joe Biden, is able to again win a presidential race.

Watch the event in the player above.

The Biden campaign is laying out what it sees as its path to keeping the White House in a new memo sent to its staffers Thursday, saying that winning the “blue wall” states of Wisconsin, Pennsylvania and Michigan is the “clearest pathway” to victory.

Though senior aides write in the memo that they could clinch 270 electoral votes in a number of ways, the new memo, obtained by The Associated Press, says those three states are critical and why Biden has prioritized the areas in his recent travels. He went to Madison, Wisconsin; Philadelphia and Harrisburg, Pennsylvania over the weekend, and will head to Detroit on Friday.

The fresh emphasis on the “blue wall” states by the campaign, which has heavily invested in other battlegrounds such as Arizona, Nevada, North Carolina and Georgia, acknowledges that the path to defeating Donald Trump in November is narrowing, even as the team insists the Sun Belt states are “not out of reach.”

It acknowledges “real” movement in the race, but argues that it was not a “sea change.”

The memo, from campaign chair Jen O’Malley Dillon and campaign manager Julie Chavez Rodriguez, also contends that Biden remains the strongest Democratic opponent to Trump, the presumptive Republican nominee.

“There is also no indication that anyone else would outperform the president vs. Trump,” the memo says. “Hypothetical polling of alternative nominees will always be unreliable, and surveys do not take into account the negative media environment that any Democratic nominee will encounter. The only Democratic candidate for whom this is already baked in is President Biden.”

Campaign leaders say they want to continue touting Biden’s achievements in office, drawing a contrast with Trump and his policies, and redoubling their grassroots efforts to engage voters — which were their goals anyway before the disastrous June 27 debate that left in question Biden’s cognitive capabilities and fitness to serve. Their internal research suggests that voters will make their decisions based on policies and issues, rather than Biden’s age, O’Malley Dillon and Rodriguez contend.