MACKINAC ISLAND, Mich. — Donald Trump has long heralded Michigan as the crown jewel of his 2016 victory. But the president's campaign team is increasingly grim about a repeat performance in the traditionally blue Rust Belt state.

After a midterm election that decimated the ranks of Michigan Republicans, Trump's campaign is looking to other battlegrounds he lost last time — such as Minnesota and New Hampshire — that they see as more promising.

The assessment illustrates how Trump’s support in the Rust Belt states that propelled him to the presidency has softened, jeopardizing his prospects for a second term. While they say it’s too early to write off Michigan — Trump aides say the campaign still intends to pump resources into the state — a range of public polling has shown Trump in poor shape here.

“It’ll be tough,” said Greg McNeilly, a veteran GOP strategist in Michigan. Though the president overcame tough odds in 2016, winning the state by 10,704 votes, or less than 1 point, McNeilly expects Democratic turnout to be stronger in 2020. “Trump is the underdog,” he said.

With questions mounting about the president’s standing in the state, senior GOP leaders convened this weekend for the biennial Mackinac Republican Leadership Conference on the picturesque northern Michigan island. The event drew Vice President Mike Pence and House Minority Leader Kevin McCarthy, among a range of other GOP officials.

As lawmakers, operatives, and lobbyists traded gossip on the porch of the iconic Grand Hotel, many of them shrugged off concerns about how Trump would fare in Michigan next year. Jamie Roe, a top Republican strategist in the state, rejected the idea that the president would abandon the state as Mitt Romney and John McCain did in previous presidential campaigns.

Trump, Roe argued, has built an enduring connection to blue-collar voters in areas like Macomb County, which the president won in 2016 after Barack Obama carried it four years earlier. The eastern Michigan county, long seen as a bellwether for the state, is the birthplace of so-called Reagan Democrats.

“I can tell you this: the president is stronger today than he was in 2016 in Macomb County,” said Roe, himself a Macomb resident. “I guarantee he will do better in Macomb County and I fully expect the president will be there before this campaign is over.”

Republican officials say they're planning a substantial investment in Michigan, with 20 full-time staffers expected to be deployed to the state by the end of the year. This weekend the White House dispatched Pence to the off-the-grid island, where he reminisced to the 1,400-plus conference attendees about the boisterous rally he and Trump held in Grand Rapids the night before the 2016 election.

Pence chief of staff Marc Short said the appearance would be part of a broader effort to deploy the vice president to Midwestern states. The former Indiana governor has visited Michigan three times this year.

“I think the vice president, as a Midwestern governor, was helpful to the ticket in Midwestern states that flipped in 2016. And I think there’s no doubt he’ll be spending a lot of time here heading into 2020,” said Short. “There will be plenty more trips here in Michigan.”

Trump's biggest challenge in the state — and the main source of his campaign’s concern — is Wayne County, a liberal population center encompassing the Detroit metro area. Hillary Clinton won the county last time by just 289,000 votes; by contrast, Obama carried it by 382,000 votes four years earlier. Even partially closing that gap would put Democrats, who have lost the state only once since 1988, in the driver's seat.

Trump allies say Clinton took the state for granted and failed to mobilize voters in heavily black Detroit — a mistake Democrats aren’t likely to make again.

His political team has spent extensive time delving into voter data throughout the Rust Belt and concluded that Wisconsin and Pennsylvania — the two other battlegrounds that tipped the scales for Trump — lack a similar urban center where Democrats failed to turn out their base.

Republicans are focused keenly on Wayne County now. During a 2020-focused briefing at the White House this summer, the president asked advisers for their views on the Democratic contenders. Republican National Committee Chairwoman Ronna McDaniel, a former Michigan GOP leader, said Kamala Harris could pose a threat due her potential appeal in the county.

Wayne County was also at the root of a dispute between the campaign and Senate GOP leaders over Republican Senate candidate John James earlier this year. Before James entered the contest, the campaign relayed concerns to the National Republican Senatorial Committee that James' bid could spur Democrats to invest more heavily in the state. At one point, the president’s advisers penned a memo to the committee detailing how a James Senate campaign could drive up Democratic turnout and potentially hurt Trump’s prospects.

Senate GOP leaders who recruited James strongly disagreed. They argued that the 38-year-old military veteran, widely regarded as a rising star, would give the party its strongest statewide ticket and boost the president.

Many Republicans at Mackinac argued that winning Michigan won't be so easy for Democrats. Some predicted a backlash against Democrats, who now hold all of Michigan’s statewide offices. Others downplayed early polling in the presidential race because Trump's potential rivals haven't been put through the general election wringer.

Others said if Democrats nominate a liberal candidate like Elizabeth Warren or Bernie Sanders, it could risk alienating moderate voters they need to win the state.

McCarthy predicted the rival party would select Warren as the nominee, hurting Democrats throughout the Rust Belt.

“I think they’re moving too far [left] and they’re acting emotionally,” McCarthy said.

If Trump loses Michigan and its 16 electoral votes, it wouldn’t necessarily cut off his path to reelection. The president won 304 electoral votes in 2016, meaning he still has a cushion keeping him above the 270 threshold. But if his problems in the state bleed over to Wisconsin and Pennsylvania, which collectively account for 30 electoral votes, it could well doom his chances.

Still, some Republicans at the conference said the GOP's troubles in Michigan go beyond the presidential race to down-ballot contests.

As they walked the halls of the Grand — its lobby adorned with photographs documenting past visits from Republican luminaries like George H.W. Bush, Gerald Ford, and Ronald Reagan — some attendees buzzed about House races. The party has so far failed to land top-tier recruits in two Michigan congressional districts they lost in 2018, raising concerns about whether they will be able to make a serious play to win them back next year.

Yet the weekend contained some brighter news for the party. After suffering a raft of congressional retirements, one longtime member appears poised to seek reelection: Michigan Rep. Fred Upton. While he has yet to formally announce his intentions, the congressman, who was first elected in 1986, spent the weekend handing out “Upton 2020!” buttons.

Upton, a moderate who at times has broken with the president, was used to coasting to reelection. But last year he barely hung on, fueling speculation he might join other House Republicans fleeing for the exits.

Upton said party leaders have been leaning on him hard.

“If we don’t run,” he said, “it makes it a very competitive seat.”