The U.S. President has tried to downplay the importance of 100-day mark, perhaps out of recognition that many of his campaign promises have gone unfulfilled.

“We are not going to let other countries take advantage of us any more,” he said on Saturday in Harrisburg at the Pennsylvania Farm Show Complex and Expo Centre. “From now on it’s going to be America first.”

But even as he returned to friendly political turf in Pennsylvania, Mr. Trump seems caught between his role as an outsider candidate and that of a now-elected negotiator.

Even with his return to Pennsylvania, Mr. Trump seemed torn between who he was courting. He opened the rally with an extended attack on the media, pointing out that he was choosing to stay away from the annual White House Correspondents’ Association dinner.

“I could not possibly be more thrilled than to be more than 100 miles way from Washington’s swamp,” he said, “spending my evening with all of you and with a much, much larger crowd and much better people, right?”

The State was critical to Mr. Trump’s victory over Democrat Hillary Clinton in November 2016. Mr. Trump won Pennsylvania with 48% of the vote, the first time the State had voted for a Republican presidential candidate since George H.W. Bush in 1988.

Mr. Trump visited the AMES Companies in Pennsylvania’s Cumberland County, a shovel manufacturer since 1774. With that backdrop he signed an executive order directing the Commerce Department and the U.S. trade representative to conduct a study of U.S. trade agreements. The goal is to determine whether America is being treated fairly by its trading partners and the 164-nation World Trade Organisation.

Mr. Trump’s rally on Saturday night in Harrisburg offered a familiar recapitulation of what he and aides have argued for days are administration successes, including the successful confirmation of Neil Gorsuch to the Supreme Court, his Cabinet choices and the approval of construction of the Keystone XL pipeline.

Meanwhile, North Korea’s missile launch on Saturday signalled its continued defiance against the U.S., China and other nations, on which Mr. Trump tweeted: “Bad!”

Asked during an interview for CBS’ “Face the Nation” if military action would follow a nuclear test by the North, Mr. Trump responded: “I don’t know. I mean, we’ll see.”

At the 100-day mark, polls suggest that Mr. Trump’s supporters during the campaign remain largely in his corner. Though the White House created a website touting its accomplishments of the first 100 days, Mr. Trump has tried to downplay the importance of the marker, perhaps out of recognition that many of his campaign promises have gone unfulfilled.

“It’s a false standard, 100 days,” Mr. Trump said while signing an executive order on Friday, “but I have to tell you, I don’t think anybody has done what we’ve been able to do in 100 days, so we’re very happy.”

Mr. Trump is turning to what he’s billed as the nation’s biggest tax cut. It apparently falls short of Reagan’s in 1981, and tax experts are sceptical that the plan would pay for itself, as Treasury Secretary Steve Mnuchin has claimed.

The economy, so far, has been Mr. Trump’s ally. Polls show that Americans feel slightly better about his job performance on that subject than his job performance overall.