Schuette, the state attorney general who has trailed in polls, pointed to Donald Trump's surprise 2016 victory in Michigan, when some final-week surveys showed Hillary Clinton slightly ahead while others had it as a close race.
"A funny thing happened on the way to the White House. A funny thing is going to happen on the way to the governor's house," Schuette said at the state GOP headquarters in Lansing, where volunteers were calling potential voters. "We're going to win this because (of) the desire to make sure we build on the success of the last eight years and we can't go back."
Unlike in 2016, Whitmer has led or has been slightly ahead in every poll in the race to succeed term-limited Republican Gov. Rick Snyder. The former legislative leader said she was taking nothing for granted, however.
"We have resisted, we have protested, we have marched, we have rallied," she told supporters at a Grand Rapids brewery, citing the Women's March and protests against Republican health care and immigration policies. "All of this ... none of it matters if we don't keep our foot on the gas these last 36 hours."
Whitmer — whom Schuette has criticized for voting to raise taxes in the past — listed a series of issues that are "on the ballot": clean drinking water, LGBT civil rights, the Medicaid expansion she helped pass, GOP education policies influenced by the conservative DeVos family and women's reproductive rights. Schuette pointed to the economic recovery while urging against going "backward" with Whitmer.
The governor's race is among many big contests on Tuesday's ballot, including third-term U.S. Sen. Debbie Stabenow versus Republican challenger John James.
"She must be held accountable to the people. I represent the people, not a political class who dictates to us," James, a combat veteran and businessman, said during a stop at an orchard in Macomb County's Washington Township. He continued to criticize Stabenow as a career politician who does not have what it takes.
Stabenow, speaking at a canvass kickoff in Madison Heights, accused James of being with Trump "2,000 percent" and said "who we are as Americans" is on the ballot. "We reject the racism, the hatred, the bigotry," said Stabenow, who had led in polling.
Michigan's election also features closely watched congressional races, contests that will determine control of the GOP-led Legislature and battles for two other top offices opening due to term limits: attorney general and secretary of state. Republicans have controlled state government for eight years.
Election officials are preparing for what could be high turnout for a midterm election. The state released figures Monday showing that nearly 1 million people had cast an absentee ballot — a 300,000-vote, or 43 percent, increase from 2014. More ballots were still being mailed in.