The exposition was opened in the spring of 1901 by the new vice president, Theodore Roosevelt. President McKinley had been scheduled to do the honors but had to cancel because of his wife's illness. It was not until September that the McKinleys were able to inspect the exposition grounds. On the morning of September 5th, the president and first lady crossed the Triumphal Causeway and entered the fair grounds in an open carriage preceded by troops, military bands, and a mounted honor guard. The president gave a major address on trade policy to a large crowd gathered on the Esplanade. Afterwards he toured the exhibits, complimenting all. He had an unscheduled coffee at the Porto Rican Building with the Latin American commissioners.
The following day, the presidential party took an excursion by rail to see Niagara Falls. Upon returning to Buffalo, McKinley returned to the exposition grounds for a reception in the Music Building. The president had been standing in a receiving line greeting the public for seven minutes when an anarchist named Leon Czolgosz shot McKinley twice at point blank range. Despite early hopes that he might survive the attack, a week later the president died, whispering the words of his favorite hymn, "Nearer my God to Thee, Nearer to Thee."
The vigorous forty-two year-old Progressive, Theodore Roosevelt, was now in the White House. The nineteenth century was over and the modern era had begun. Old Guard party boss Mark Hanna complained to a colleague, "Now look! That damned cowboy is president of the United States!"