Kamala Harris targets the Rust Belt while Donald Trump heads to the biggest US swing states Sunday in a frantic last push, less than 48 hours before Election Day in the historically close campaign.

Seventy-five million people have cast early ballots ahead of Tuesday's climax and the race is down to the wire — with more states functionally tied in polls at this point than in any comparable election.

As of Saturday evening, neither candidate had a margin greater than three points in any of the seven battleground states set to determine the presidency, according to the polling averages maintained by RealClearPolitics.

Harris — desperate to shore up the Great Lakes states seen as essential to any Democratic ticket — was to spend the day in Michigan, beginning in Detroit before a stop in Pontiac and an evening rally at Michigan State University.

Trump's Sunday timetable centers on Pennsylvania, North Carolina and Georgia, the three biggest prizes in the "Electoral College" system that awards states influence according to their size. 

The 78-year-old has been scrambling to distract from the now week-long scandal around his rally at New York's iconic Madison Square Garden in which warm-up speakers alienated Hispanics and women with racist and sexist language.

Trump surrogates winced at the unforced error, which looked especially unprofessional when contrasted with Harris's speech to a massive, jubilant crowd on Washington's Ellipse, with the White House providing the backdrop.

None of Trump's Sunday events take place in areas with large Hispanic populations but Pennsylvania is the swing state with the most Puerto Ricans, a community particularly angered by the bigotry at Trump's rally.

"The choice could not be clearer for Pennsylvanians: President Donald J. Trump stands for America First policies while Kamala Harris represents incompetence and dangerously liberal policies that are devastating Pennsylvania families," the Trump campaign said.

'Split screen'

Michigan is one of the seven closely watched battlegrounds.

Trump flipped the "Great Lake State," a former Democratic stronghold, on his way to defeating Hillary Clinton in 2016. President Joe Biden returned it to the Democratic column in 2020, buoyed by unionized workers and a large Black community.

But this time, Harris risks losing the support of a 200,000-strong Arab-American community that has denounced Biden's handling of the Israel-Hamas war in Gaza.

Pollsters have noted an erosion in Black support for the Democratic ticket and Harris's aides acknowledge that they still have work to do to turn out enough African American men to match Biden's winning coalition in 2020.

In a bid to reach out beyond her traditional support bases, Harris wrapped a day on the campaign trail Saturday with a surprise appearance on "Saturday Night Live," mocking her presidential election rival Donald Trump on the iconic sketch show.

"Keep Kamala and carry on-ala!" the vice president said in a well-received appearance alongside Maya Rudolph, the comedian who has been playing her as "America's fun aunt" on the show.

Keen on as much TV exposure as possible, the Harris campaign has booked a two-minute spot to air Sunday during football games, including a tie between two NFL teams from the crucial swing states — the Green Bay Packers against the Detroit Lions. 

In the ad, Harris pledges to be "a president for all Americans" and promises to "build a brighter future for our nation." 

"The campaign's research shows that the last week has proven decisive in cementing the choice in this election with both undecided and lower-propensity voters," her campaign said.

"The closing argument split screen of Madison Square Garden and its fallout against the Ellipse has broken through and crystallized the choice for this slice of the electorate."

Harris, 60, got a boost Saturday as the final Des Moines Register poll before Election Day — seen as a highly credible test of wider public sentiment — showed a stunning turnaround, with Harris ahead in a state won easily by Trump in 2016 and 2020.

She leads by three points in a poll that showed her trailing Trump by four points in September.

by Roberto Schmidt with Frankie Taggart in Washington