GOP presidential nominee Donald Trump has had his say. Thursday night's closing speech to the Republican National Convention was his opportunity to deliver an uplifting and hopeful vision of America. Instead, he offered darkness and despair.

Make no mistake, America has big problems. The nation's immigration issues date back to President Ronald Reagan's amnesty in the 1980s. We have budget deficits and economic problems traceable to President George W. Bush's first term. Mortgage and banking crises have roots in President Bill Clinton's administration.

Abroad, we've had military disasters. The Iraq War was the biggest foreign policy blunder since Vietnam. Afghanistan continues to be the graveyard of empires. Go back as far as the 1983 bombing of the U.S. Marines barracks in Beirut, Lebanon, and the awful 1979 attempt by President Jimmy Carter to rescue 52 American hostages held in Iran. Every administration has experienced victories and defeats that have reverberated to the present.

But Trump, often shouting with a gravelly and menacing voice, laid blame for America's problems - including crime at home, radical Islamic terrorism abroad - at the feet of exactly two people: President Barack Obama and Democratic presidential candidate Hillary Clinton. It's as if the entire modern American experience occurred in a vacuum, stripped bare of historical precedent.

In his entire 75-minute speech, Trump made no mention of the GOP-led Congress. He offered a vision of America's future alliance with NATO as one in which U.S. treaty obligations - enacted into law and revocable only by Congress - have no bearing. Under Trump's rule, the commitment to defend our allies would depend solely on his assessment of what they've done for us lately.

His was a vision of an imperial presidency that mirrors the image Trump cultivates for himself. Unassailable, impervious, unapologetic.

The convention was shunned by almost every Republican of note. Trump's main primary opponent, Texas Sen. Ted Cruz, refused to endorse him. Former candidate Mitt Romney stayed away, as did the only two living former Republican presidents and the GOP host governor of Ohio, John Kasich.

Plagiarism issues marred a speech by Trump's wife, Melania. In short, what was supposed to be a convention victory lap instead drew attention to Trump's severe weaknesses as a manager, unifier and defender of democracy. Against that backdrop, it's understandable why darkness and despair were his prevailing themes.

REPRINTED FROM THE ST LOUIS POST DISPATCH