MIAMI >> Convinced that his surprising victory in Michigan represented a turning point, Sen. Bernie Sanders and his advisers are maneuvering and spending aggressively to pull off a huge upset on Tuesday — a victory in the Ohio primary — by focusing on Hillary Clinton’s past support for trade deals that are deeply unpopular in the Midwest and other key states in his updated battle plans.

Sanders seemed newly energized and tactical as he sat by a pool at his Miami hotel and predicted that Tuesday’s win was just the beginning of a phase of the campaign that he would dominate. Saying that coming primaries and caucuses look unusually promising for him, he described plans to crisscross the country arguing that Clinton championed policies that wrecked lives. He also said he would tell voters that he was the strongest candidate to put up against Donald Trump, the Republican front-runner.

“We are heading to the Midwest. We are going to Ohio. We are going to Illinois, going to Missouri, drop into North Carolina,” Sanders said. “These states in the Midwest are going to respond to us and our message in the same way Michigan workers did, and that is, ‘We need an economy that works for all of us and not just the 1 percent. We need a trade policy that creates jobs in America. Not in China or in Mexico.’”

“I think the future now bodes well for us because we are moving out of the Deep South where we have not done well,” he continued.

Advisers to Sanders said they had increased television advertising spending significantly in Ohio, broadcasting a new commercial criticizing free trade as well as other ads about Wall Street, jobs, Social Security and other themes. They were also dispatching key staff members to the state, and weighing last-minute visits by the candidate to parts of Ohio that Democratic candidates typically ignore, while relying on prominent supporters like former State Sen. Nina Turner to help turn out voters in cities like Cleveland.

Several Democratic strategists and pollsters said they now thought Sanders could win the Ohio primary — and perhaps Illinois and Missouri — after the senator performed unexpectedly well among independents and young people in Michigan and also beat Clinton by more than 10 percentage points with white voters there, according to exit polls. Sanders also won support from about 30 percent of Michigan’s black voters, a larger share than in recent contests in the South, a sign that he might be able to stop Clinton from winning the landslides she is aiming for in predominantly black neighborhoods in Chicago, Cleveland and St. Louis.

“After Michigan, Bernie can certainly win Ohio, and frankly you cannot write him off in any major urban metropolitan state anymore,” said Peter D. Hart, a veteran Democratic pollster. “He has hit a perfect dynamic that few of us expected: He is campaigning on issues like economic insecurity and inequality that are central in this election, he is not seen as overtly political, and he has an ability to contrast himself with every other candidate by being frank and authentic.”

Ohio, a bellwether swing state in presidential elections, is particularly crucial for Sanders because a victory could increase concerns about her vulnerabilities in a general election. His free trade argument has become an enviable weapon with blue-collar workers in Ohio and other Rust Belt states because his longtime opposition to trade pacts is a rare and clear policy difference with Clinton, who has supported deals like the North American Free Trade Agreement and still argues that trade can benefit U.S. workers.

“If Sanders wins Ohio, there is a new narrative for the next three months and the nomination fight goes on to the California primary on June 7 in a way that no one ever predicted,” said Robert Shrum, a veteran political adviser to several Democratic presidential campaigns. “Ohio would give Sanders further legitimacy and the standing to go all the way to the convention and make the case to superdelegates there that he is better able to win in November.”

Yet, Sanders also admits that it will not be easy to erase Clinton’s delegate lead, but he is convinced he can persuade superdelegates, who can support any Democratic candidate for the nomination, to back him if he wins enough states.

Superdelegates could become critical if neither candidate has clinched the nomination when the contests end in June. Such was the case in 2008: Barack Obama had a lead over Clinton of about 100 pledged delegates in June, but not enough to secure the nomination. But he did have support from enough superdelegates to put him over the top, and Clinton — under pressure to unite the party — chose not to go to the Democratic convention to try to peel away his superdelegates.

Clinton now has 214 more pledged delegates than Sanders, and support from 461 superdelegates to his 25. Superdelegates are not bound by the popular primary vote. (The Republicans do not have superdelegates.)

Clinton’s advisers expressed confidence that no matter how many more narrow victories Sanders won in major states like Michigan, he would never overtake her in the pledged delegate count — and that superdelegates would stand by her. Advisers for Sanders said their candidate was unlikely to win more delegates than Clinton on Tuesday, adding that they hoped to come close and then start winning more delegates in contests starting in late March.

Sanders has also been increasingly talking about a West Coast strategy and not just in California, which has a whopping 546 delegates at stake. Democrats in Washington state, Alaska, Idaho, Utah and Wyoming hold caucuses, a voting format that has favored Sanders, and his supporters are hopeful that he could prevail in those states, as well as in Oregon.

Tad Devine, the campaign’s senior adviser, said Sanders would soon have television and digital advertising in the five states voting on Tuesday — Florida, Illinois, Missouri, North Carolina and Ohio. He also described the race as developing in phases now.

“The general picture is this: Our goal for next Tuesday is to win as many delegates as we can, if we can win states, too, that would be great,” Devine said. “We are then going to go into a period of the process where we believe we have great opportunities to win a lot of contests in states and to beat Hillary Clinton.”

© 2016 The New York Times Company