In an unconventional presidential race, Donald Trump is making yet another unconventional move: campaigning in liberal Portland for the second time this year even though most Republicans consider the more conservative 2nd Congressional District as his best bet to pick up an electoral vote in Maine.

On Saturday, a campaign official said Trump would be in Portland on Thursday, but details of the visit had yet to be worked out. As of Sunday night, his official schedule did not reflect the visit.

“It is unusual to see a Republican (presidential) candidate come to Portland,” said Jim Melcher, a political science professor at the University of Maine in Farmington. “But having Trump as a candidate in this election, maybe the map won’t be as predictable as it has been in recent years.”

“The map” is shorthand for the Electoral College map – and presidential nominees Trump and Hillary Clinton are in a race to capture the 270 electoral votes needed for election.

Most states are comfortably locked up as “red” or “blue” states, and presidential candidates traditionally spend the final 100 days until Election Day focused on wooing votes in swing states with a large number of electoral votes, such as Florida, Ohio and Pennsylvania.

But Maine, with its four electoral votes, hasn’t voted for a Republican presidential candidate since 1988, when voters chose the home-state favorite, Vice President George H.W. Bush, over Michael Dukakis. That’s made Trump’s decision to campaign here a surprise for political observers, including some Republicans.

But Maine, instead of the usual winner-take-all electoral vote system in most other states, has a split electoral vote system. That means the winner in each congressional district is awarded one electoral vote, and the statewide winner gets the remaining two electoral votes. Although Maine adopted the split-vote system in 1972, the state has never split its votes and all four have gone to the same candidate.

But that could change, says Maine Senate Majority Leader Garrett Mason, R-Lisbon Falls. Trump’s visit to Portland is a sign to him that Maine is “in play” on the national stage.

“Maine is no longer the deep blue state it has traditionally been, so Trump is going to play here,” said Mason, who initially backed Sen. Ted Cruz of Texas. “He is going for three electoral votes, maybe even four.”

Maine Republicans selected Cruz over Trump during the party’s caucuses in March.

Mason said evidence of the state’s shift rightward can be seen in the re-election of Gov. Paul LePage in 2014, and control of the state Senate going back and forth between Republicans and Democrats in recent years, instead of being reliably Democratic-controlled.

“You cannot predict what the people of Maine are going to do, and it’s very exciting,” Mason said. “It’s fun. We’re going to be on the map.”

Jason Savage, executive director of the Maine Republican Party, agreed.

“Our field operation has been out talking to voters for months and we’ve seen the support for Mr. Trump,” Savage said Sunday. “I think they’re ready for change and I think Donald Trump represents that change.”

Savage noted that the latest predictions from political analyst and statistician Nate Silver, on his website fivethirtyeight.com, show Trump favored to win the 2nd District, which stretches from western Maine to northern and eastern Maine and is the largest congressional district geographically east of the Mississippi River.

But University of New England political science professor Brian Duff says he doesn’t think Maine will have a role nationally in the election.

“I don’t think Maine is in play,” Duff said Sunday. “There is some small chance (Trump) could have unique appeal in the 2nd District.”

Duff thinks Trump is campaigning in Maine because he likes LePage: “I do think it’s that simple. He likes LePage and he figures if he can win here, why not Trump?”

Trump would be the first candidate to visit Maine since the recently concluded national party conventions. He has visited the state twice already this year: Portland in March, shortly before the March 5 Republican presidential caucuses, and Bangor on June 29.

More details about the Trump event Thursday in Portland were not available on Sunday, and state and national representatives of the Trump campaign did not return calls for comment. LePage’s communications team did not respond to questions about whether the governor would attend the event. LePage has appeared with Trump at his previous campaign events in Maine.

Jessica Grondin, a spokeswoman for the city of Portland, confirmed Sunday night that the city and its police department will be involved in preparations and traffic control for Trump’s arrival, but said in an email that the city does “not know the details in terms of location as of yet. We should know more tomorrow.”

An official with the Clinton campaign in Maine said there are no scheduled visits to Maine by the candidate.

A poll by the Portland Press Herald/Maine Sunday Telegram in late June showed Trump had an overall favorability rating of just 28 percent in Maine, compared to Clinton’s 36 percent.

However, the poll, conducted by the University of New Hampshire Survey Center, showed the two in a virtual tie in the presidential race in the 2nd District, which includes Lewiston and Bangor. Among likely voters in the district, Trump had the support of 37 percent, while Clinton had 36 percent.

Rep. Ellie Espling, R-New Gloucester, said she wasn’t sure what to make of the Trump visit, echoing others who say it’s really the 2nd District where he has a chance of picking up momentum.

“He has sort of hinted that maybe Maine (is) a place he can have some success,” she said. “I wouldn’t be surprised if that’s part of his motivation to come to Maine.”

Staff Writer Dennis Hoey contributed to this report.