The 926 delegates to the Republican convention, which met in Philadelphia on June 19–21, re-nominated William McKinley by acclamation. Thomas C. Platt, the "boss" of the New York State Republican Party, did not like Theodore Roosevelt, New York's popular governor, even though he was a fellow Republican. Roosevelt's efforts to reform New York politics – including Republican politics – led Platt and other state Republican leaders to pressure President McKinley to accept Roosevelt as his new vice- presidential candidate, thus filling the spot left open when Vice President Garret Hobart died in 1899. By electing Roosevelt vice president, Platt would remove Roosevelt from New York state politics. Although Roosevelt was reluctant to accept the nomination for vice president, which he regarded as a relatively trivial and powerless office, his great popularity among most Republican delegates led McKinley to pick him as his new running mate. Quite unexpectedly, Roosevelt would be elevated to the presidency in September 1901, when McKinley was assassinated in Buffalo, New York.