BUFFALO, New York -- A quarter-century ago, only the most wild-eyed, optimistic, maybe slightly crazy visionary could have imagined the Buffalo of today: a modern, tech-oriented city that has transformed rubble into revitalization, taken a tired waterfront and made it a breathtaking walkway, and watched its museums grow from local treasures into major national attractions.

This weekend, a forbidding 145-year-old mental institution reopens as a glittering hotel. With its General Mills plant and its colleges, Buffalo is more than ever a city of grain elevators and brain elevators. Optimism, along with the smell of Cheerios, is in the air.

It's a transformation -- a happy one, for a change -- that gives hope in an era of despair. For while distress, even hopelessness, is all around us, from Syria to North Korea and on both ends of Pennsylvania Avenue in Washington, Buffalo offers us a reminder that this is an unusual period of unresolved issues.

We have faced periods of difficulty, where the ultimate resolution of our challenges was never clear, many times before. We now know that the Union was preserved in the middle of the 19th century, but in 1861 that was no safe bet. We now know that the Allies prevailed in World War II, but in early 1942 that was not the least bit apparent. We now know that the walls of segregation, and the walls of Soviet-style communism, would fall, but in 1963 that was no sure thing.

So here are some of the open questions to which our grandchildren will know the answers, and, if we are lucky, may even wonder what all the worry was about:

-- Global warming. Let's agree where there is broad agreement: Climate change is real, and a real threat to our lifestyle. High water, indeed a foot and a half higher than usual for springtime, along Lake Ontario in nearby Niagara County is causing grave concern around here, and while climate change may not be the reason -- water-level controls and an especially wet spring may be the culprit -- the effects are broadly similar: dramatic erosion of the lake bank, flooding at yacht clubs and boat slips, beach staircases swept away, a state of emergency in four lakeside towns.

President Donald J. Trump and environmentalists are at loggerheads (though -- speaking of change -- we should remember that the last major log drive in the continental United States occurred more than four decades ago in Maine, rendering that metaphor a historical artifact). Even so, the perils and opportunities are clear. Continued warming is a real danger, not to be underestimated; some populations of birds, fish and mammals have declined by more than half in about a half-century. But from Great Britain also comes small glimmers of hope based on conservationists' success in saving the saiga antelope, the echo parakeet and the giant panda. Small victories, but perhaps precursors.

-- Confrontation with North Korea. President Barack Obama told his successor that North Korea, its angry fists full of nuclear weapons, would be his biggest challenge. He was right. The isolated nation probably does not have the capacity to reach even Hawaii by missile today, but soon will, with the West Coast vulnerable before the decade is out.

This is a serious threat to American security and to the American way of life, which would be shattered beyond recognition by a credible threat of nuclear attack. Washington knows that, but so does Pyongyang. Thus, this is what the Israelis call an existential crisis. It is imminent, and it may be unavoidable.

Right now we have no idea how this crisis will be resolved. It is likely that Trump and his North Korean counterpart have no idea either. But barring an unforeseen crisis elsewhere -- and real crises often are unforeseen -- this may be the defining confrontation of the Trump administration. Like so much in this age of the digital and the disruptive, it is a problem that is essentially binary, the result being triumph or tragedy.

-- The Trump presidency. The new president is caught between three competing interpretations: that his improvisational style and combative iconoclasm represent a meeting of the man and the moment; that he and Republican congressional leaders will be able to forge an uneasy but productive peace; and that his manners and impulses, political and personal, are a disgraceful aberration from presidential tradition.

His supporters point to the precedent of Harry Truman, often reviled during his presidency as out of his element, but now regarded as an elemental force and a successful chief executive. His detractors object to any argument that seeks to "normalize" his behavior. This represents the great divide in American life today. A solid majority of Americans, according to the latest Wall Street Journal/NBC News poll, disapprove of his performance. The gap between his approval and disapproval rates among independents has nearly tripled since February. That doesn't necessarily speak to his historical ratings, but it will affect his ability as president to perform well enough to boost his profile in history.

-- America's role in the world. The president has spoken often of an "America first" approach to diplomacy, but in the past month has shifted dramatically, reacting to horrific pictures of victims of chemical-weapons attacks by intervening with air attacks.

-- Whatever other virtues the 45th president possesses, he lacks the ability to craft a sharply defined philosophy. In this regard, but probably in no other, he resembles Franklin Roosevelt, whom Walter Lippmann derided as having a second-class intellect but who, as the 1930s financial crisis deepened and as world war approached and was prosecuted, developed strong thematic views.

It is no smarter to define Trump's worldview after 100 days than it would have been to define the worldview of John F. Kennedy after 100 days -- a period that included the Bay of Pigs fiasco, followed in June by a disastrous summit with Nikita S. Khrushchev, who by Kennedy's own admission "beat the hell out of me," producing what the president told New York Times reporter James Reston was the "worst thing in my life. He savaged me."

It is the next several months, and perhaps the next year, that will provide hints of the Trump view of diplomacy and national security. My guess is that that view will be unrecognizable to today's analysts. That does not mean they will be comforted. It only means that they will be surprised.

(David M. Shribman is executive editor of the Post-Gazette (dshribman@post-gazette.com, 412 263-1890). Follow him on Twitter at ShribmanPG.)

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