President Joe Biden visited Northern Ireland on Wednesday to help mark the 25th anniversary of the Good Friday Agreement, which brought peace to this part of the United Kingdom, as a new political crisis tests the strength of that peace.

On his first presidential visit to Northern Ireland, Mr. Biden stressed that American investment can help fuel economic growth – especially if the fractious politicians in Belfast resolve a new political crisis that has rattled the Good Friday peace deal and put Northern Ireland's government on pause.

"Supporting the people of Northern Ireland, protecting the peace, preserving the Belfast Good Friday Agreement is a priority for Democrats and Republicans alike in the United States, and that is unusual today because we're very divided in our parties," Mr. Biden said in a speech at Ulster University's new campus in downtown Belfast. "This is something that brings Washington together, it brings America together."

The president said "scores" of American companies are eager to come to Northern Ireland and stressed that "peace and economic opportunity go together." Mr. Biden announced that Joe Kennedy, U.S. special envoy to Northern Ireland for economic affairs, will lead a trade delegation of American companies to Northern Ireland later this year.

"Your history is our history, and even more important, your future is America's future," he said. "Today's Belfast is the beating heart of Northern Ireland, and it's poised to drive unprecedented economic opportunity and investment, from communities across the U.K, across Ireland and across the United States."

U.S. involvement was key to negotiating the Good Friday accord, which largely ended decades of sectarian violence that killed 3,600 people. While that peace has endured, Northern Ireland is currently without a functioning government.

Stormont, the seat of its assembly, has been suspended since the Democratic Unionist Party, which formed half of a power-sharing government, walked out a year ago over a post-Brexit trade dispute.

"The United States of America will continue to be your partner in building the future that young people in our world deserve," Mr. Biden said. "It matters to us, to Americans, and to me personally. It genuinely matters."

The trip kicked off with a security breach, Northern Ireland police officials confirmed to CBS News on Wednesday morning. Police offiicals said the security breach involved a document that had an operational order which outlines officer deployments, but no personal details on the president, his officials or that of other dignitaries associated with the visit were included within the document. 

Mr. Biden's schedule on Wednesday began over tea with British Prime Minister Rishi Sunak. Asked what he would tell the leaders of Northern Ireland's five main political parties when he meets with them later in the day, Mr. Biden responded, "I'm going to listen."

Amanda Sloat, the National Security Council's senior director for Europe, said that while Mr. Biden wants to see the Stormont government back up and running, he won't try to strongarm Northern Ireland's politicians back to the table.

"The purpose of the president's visit today is to mark the Good Friday Agreement, to continue to reaffirm the support of the United States for peace and prosperity," she said. "The president's message ... is the United States' strong support for that, the belief that the people of Northern Ireland deserve to have a democratically elected power sharing representative governance."

Mr. Biden said in his speech in Belfast that he believes the democratic institutions established through the Good Friday Agreement are "critical to the future of Northern Ireland." 

"An effective, devolved government that reflects the people of Northern Ireland and is accountable to them, a government that works to find ways through hard problems together is going to draw even greater opportunity in this region," he said. "So I hope the assembly and the executive will soon be restored. That's a judgment for you to make, not me."

The political crisis stems, in part, from Brexit. Britain's departure from the European Union left Northern Ireland poised uneasily between the rest of the U.K. and EU member Ireland and put the peace agreement under increased strain.

After much wrangling, Britain and the EU struck a deal in February to address the tensions over trade, an agreement welcomed by the U.S., which had urged London and Brussels to end their post-Brexit feud. The Democratic Unionist Party, though, says the Windsor Framework doesn't go far enough and has refused to return to government.

The president acknowledged Brexit created "complex challenges here in Northern Ireland," but encouraged U.K. and EU leaders to "address the issues in a way that serves Northern Ireland's best interest."

While U.K. officials hope the president's presence can help nudge the unionists back into government, Mr. Biden faces mistrust from some unionists because of his Irish American heritage. Sammy Wilson, a DUP lawmaker in the U.K. Parliament, told Talk TV that Mr. Biden "has got a record of being pro-republican, anti-unionist, anti-British."

"The track record of the president shows he's not anti-British," Sloat said, adding that "the U.K. remains one of out strongest and closest allies."

Mr. Biden is spending less than 24 hours in Northern Ireland before moving on to the Republic of Ireland for a three-day visit, including an address to the Dublin parliament, attendance at a gala dinner and trips to two ancestral hometowns. He will fly to County Louth, on Ireland's east coast, on Wednesday to visit a cemetery, tour a castle, walk around downtown Dundalk and attend a community gathering.

Neil Given, a civil servant who lives in Belfast, welcomed Mr. Biden's visit but said his "expectations are not great" that it would unblock the political logjam.

"We have prevaricated for well over a year now, and ever since the signing of the Good Friday Agreement there have been numerous stoppages of the institutions of Stormont," he said. "Whether or not Mr. Biden's visit can in 24, 48 hours pull people together and perhaps get a message we really do need to get back to government, I don't know.

"But hopefully he can do that. I know there is no more powerful person certainly to be over that can give out that message."

A massive security operation was in place for Mr. Biden's stay in Belfast, with a heavy police presence on blocked-off streets around the president's hotel and the Ulster campus.

Last month, U.K. intelligence services raised Northern Ireland's terrorism threat level from "substantial" to "severe." But Mr. Biden said then that not even the heightened risk of an attack would keep him from making the trip.

Mr. Biden last visited Ireland in 2016, when he was vice president. 

Samuel Olufemia, who is studying for a degree in public health at Ulster University, said he was looking forward to meeting Mr. Biden on campus.

"Having him in Belfast here is a privilege," said Olufemia, who is from Nigeria. "It's going to be an historic visit, and that's one of the reasons I'm excited."

In:
• Rishi Sunak
• Joe Biden
• Politics
• Northern Ireland
• European Union
• United Kingdom